Organic electroluminescent device using aryl amine derivative containing heterocycle

ABSTRACT

An organic electroluminescent device including: an anode, a cathode, an emitting layer formed of an organic compound and interposed between the cathode and the anode, and two or more layers provided in a hole-injecting/hole-transporting region between the anode and the emitting layer; of the layers which are provided in the hole-injecting/hole-transporting region, a layer which is in contact with the emitting layer containing a compound represented by the formula (1); and of the layers which are provided in the hole-injecting/hole-transporting region, a layer which is interposed between the anode and the layer which is in contact with the emitting layer containing an amine derivative represented by the formula (2).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of prior U.S. patentapplication Ser. No. 14/871,055, filed Sep. 30, 2015, the disclosure ofwhich is incorporated herein by reference in its entirety. U.S. patentapplication Ser. No. 14/871,055 is a continuation application to priorU.S. application Ser. No. 11/766,281, filed Jun. 21, 2007, thedisclosure of which is incorporated herein by reference in its entirety.The parent application claims priority to Japanese Patent ApplicationNo. 2006-172853, filed Jun. 22, 2006, the disclosure of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The invention relates to an organic electroluminescent device using aheterocycle-containing arylamine derivative.

BACKGROUND

An organic electroluminescent device (hereinafter, “electroluminescent”is often abbreviated as “EL”) is a self-emission device by the use ofthe principle that a fluorescent compound emits light by therecombination energy of holes injected from an anode and electronsinjected from a cathode when an electric field is impressed.

Since C. W. Tang et al. of Eastman Kodak Co. reported a low-voltagedriven organic EL device in the form of a stacked type device(Non-Patent Document 1), studies on organic EL devices wherein organicmaterials are used as the constituent materials has actively conducted.

In the organic EL device reported by Tang et al.,tris(8-hydroxyquinolinol)aluminum is used for an emitting layer, and atriphenyldiamine derivative is used for a hole-transporting layer. Theadvantages of the stack structure are to increase injection efficiencyof holes to the emitting layer, to increase generation efficiency ofexcitons generated by recombination by blocking electrons injected inthe cathode, to confine the generated excitons in the emitting layer,and so on.

Like this example, as the structure of the organic EL device, atwo-layered type of a hole-transporting (injecting) layer and anelectron-transporting emitting layer, and a three-layered type of ahole-transporting (injecting) layer, an emitting layer and anelectron-transporting (injecting) layer are widely known. In such stackstructure devices, their device structures and fabrication methods havebeen contrived to increase recombination efficiency of injected holesand electrons.

As the hole-injecting material used in an organic EL device, a materialhaving a phenylenediamine structure is known from Patent Documents 1 and2 and has heretofore been used widely. As the hole-transportingmaterial, an arylamine material containing a bendizine structuredescribed in Patent Documents 3 and 4 has been used.

Patent Documents 5 to 7 disclose a carbazole-containing arylaminecompound. The compound increases luminous efficiency when used as ahole-transporting material, but has such a disadvantage that the drivingvoltage significantly increases which results in an extremely shorteneddevice life.

For effective injection of holes from an anode to an emitting layer,Patent Document 8 discloses a device having two or morehole-injecting/transporting layers having ionization potential valueswhich are set in a stepwise manner. The material described in PatentDocument 8 is not satisfactory in respect both of luminous efficiencyand device life.

-   Patent Document 1: JP-A-H8-291115-   Patent Document 2: JP-A-2000-309566-   Patent Document 3: U.S. Pat. No. 5,061,569-   Patent Document 4: JP-A-2001-273978-   Patent Document 5: U.S. Pat. No. 6,242,115-   Patent Document 6: JP-A-2000-302756-   Patent Document 7: JP-A-H11-144873-   Patent Document 8: JP-A-H6-314594-   Non-patent Document 1: C. W. Tang, S. A. Vanslyke, Applied Physics    Letters, 51, 913, 1987

An object of the invention is to provide a low-voltage, high-efficiency,and long-lived organic EL device.

SUMMARY OF THE INVENTION

According to the invention, the following organic EL device is provided.

1. An organic electroluminescent device comprising:

an anode, a cathode, an emitting layer formed of an organic compound andinterposed between the cathode and the anode, and two or more layersprovided in a hole-injecting/hole-transporting region between the anodeand the emitting layer;

of the layers which are provided in the hole-injecting/hole-transportingregion, a layer which is in contact with the emitting layer containing acompound represented by the formula (1); and

of the layers which are provided in the hole-injecting/hole-transportingregion, a layer which is interposed between the anode and the layerwhich is in contact with the emitting layer containing an aminederivative represented by the formula (2).

wherein Z is a substituted or unsubstituted nitrogen-containingheterocyclic group; L₁ is a linking group formed by bonding of 1 to 4divalent aromatic groups which each may have a substituent; and Ar₁ andAr₂ are independently an aromatic hydrocarbon ring group or an aromaticheterocyclic group which may have a substituent.

wherein L₂ is a substituted or unsubstituted arylene group having 10 to40 nucleus carbon atoms; and Ar₃ to Ar₆ are independently a substitutedor unsubstituted aromatic hydrocarbon ring group having 6 to 60 nucleuscarbon atoms or a substituted or unsubstituted aromatic heterocyclicgroup having 6 to 60 nucleus atoms.2. The organic electroluminescent device according to 1, wherein theamine derivative is a compound represented by the following formula (3).

wherein Ar₃ to Ar₆ are independently a substituted or unsubstitutedaromatic hydrocarbon ring group having 6 to 60 nucleus carbon atoms or asubstituted or unsubstituted aromatic heterocyclic group having 6 to 60nucleus atoms; R₈ is a substituent; and n is an integer of 2 to 4.3. The organic electroluminescent device according to 2, wherein theamine derivative is a compound represented by the following formula (4).

wherein R₁ and R₂ are independently a substituent and may be bonded toeach other to form a saturated or unsaturated ring; and Ar₇ to Ar₁₀ areindependently a substituted or unsubstituted aromatic hydrocarbon ringgroup having 6 to 60 nucleus carbon atoms or a substituted orunsubstituted aromatic heterocyclic group having 6 to 60 nucleus carbonatoms.4. The organic electroluminescent device according to 3, wherein atleast one of Ar₇ to Ar₁₀ in the formula (4) is a substituted orunsubstituted biphenyl group.5. The organic electroluminescent device according to 2, wherein theamine derivative is a compound represented by the following formula (5).

wherein R₃ to R₅ are independently a substituent and may be bonded toeach other to form a saturated or unsaturated ring; and Ar₁₁ to Ar₁₄ areindependently a substituted or unsubstituted aromatic hydrocarbon ringhaving 6 to 60 nucleus carbon atom or a substituted or unsubstitutedaromatic heterocyclic group having 6 to 60 nucleus atoms.6. The organic electroluminescent device according to 5, wherein atleast one of Ar₁₁ to Ar₁₄ in the formula (5) is a substituted orunsubstituted biphenyl group.7. The organic electroluminescent device according to any one of 1 to 6,wherein the compound represented by the formula (1) is a compoundrepresented by the following formula (6).

wherein Cz is a substituted or unsubstituted carbozolyl group; L₃ is alinking group formed by bonding of 1 to 4 divalent aromatic groups whicheach may have a substituent; and Ar₁₅ and Ar₁₆ are independently anaromatic hydrocarbon ring group or an aromatic heterocyclic group whichmay have a substituent.8. The organic electroluminescent device according to any one of 1 to 7,wherein the compound represented by the formula (1) is a compoundrepresented by the following formula (7).

wherein Ar₁₇ and Ar₁₈ are independently an aromatic hydrocarbon ringgroup or an aromatic heterocyclic group which may have a substituent;and R₆ to R₁₃ are independently a hydrogen atom, a halogen atom, analkyl group, an aralkyl group, an alkenyl group, a cyano group, an aminogroup, an acyl group, an alkoxycarbonyl group, a carboxyl group, analkoxy group, an aryloxy group, an alkylsulfonyl group, a hydroxy group,an amide group, an aromatic hydrocarbon ring group or an aromaticheterocyclic group, which may further be substituted; adjacent atoms orgroups represented by R₆ to R₁₃ may form a ring; and L₄ is a linkinggroup formed by bonding of 1 to 4 divalent aromatic groups which eachmay have a substituent.9. The organic electroluminescent device according to 8, wherein thecompound represented by the formula (7) is a compound represented by thefollowing formula (8).

wherein Ar₁₇ and Ar₁₈ are independently an aromatic hydrocarbon group oran aromatic heterocyclic group, which may have a substituent; R₆ to R₁₅are independently a hydrogen atom, a halogen atom, an alkyl group, anaralkyl group, an alkenyl group, a cyano group, an amino group, an acylgroup, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, anaryloxy group, an alkylsulfonyl group, a hydroxy group, an amide group,an aromatic hydrocarbon ring group or an aromatic heterocyclic group,which may further be substituted; and adjacent atoms or groupsrepresented by R₆ to R₁₅ may form a ring.10. The organic electroluminescent device according to any one of 1 to9, wherein, of the layers which are provided in thehole-injecting/hole-transporting region, the layer which is in contactwith the anode contains an acceptor material.11. The organic electroluminescent device according to any one of 1 to10, which emits blue light.

According to the technology of the invention, a low-voltage,high-efficiency, and long-lived an organic EL device can be realized bythe used of a material with a specific structure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view showing an embodiment of anorganic EL device according to the invention.

FIG. 2 is a schematic cross-sectional view showing another embodiment ofan organic EL device according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The organic EL device of the invention has at least an emitting layerformed an organic compound between the anode and the cathode, and hastwo or more layers in a hole-transporting/injecting region between theanode and the cathode.

FIG. 1 is a schematic cross-sectional view of one embodiment of theorganic EL device of the invention.

In the organic EL device 1, an anode 10, a hole-injecting layer 20, ahole-transporting layer 30, an emitting layer 40, anelectron-transporting layer 50, an electron-injecting layer 60 and acathode 70 are stacked on a substrate (not shown) in this order.

In the invention, the hole-injecting layer 20 and the hole-transportinglayer 30, which are the layers present in thehole-injecting/transporting region, satisfy the following requirements(A) and (B).

(A) The layer which is in contact with the emitting layer(hole-transporting layer 30) contains a compound represented by thefollowing formula (1).

(B) The layer which is provided between the anode and the layer which isin contact with the emitting layer (hole-injecting layer 20) contains anamine derivative represented by the following formula (2).

By the provision of a layer containing a specific compound at aprescribed position in the hole-injecting/hole-transporting region, thedevice exhibits a high luminous efficiency and a prolonged device lifeat a low voltage. The reason therefor is considered as follows. Due tothe combined use of the compound represented by the formula (1) and theamine derivative represented by the formula (2), the compoundrepresented by the formula (1) exhibits its inherent property ofenhancing the luminous efficiency of the device, and uniquelyfacilitates injection of holes, thereby significantly increasing thenumber of holes to be injected into the emitting layer, and the layer ofthe compound represented by the formula (1) prevents electrons fromreaching the layer of the derivative represented by the formula (2).

In the formula (1), Z is a substituted or unsubstituted heterocyclicgroup.

Preferred examples include pyrrole, imidazole, pyrazole, triazole,oxadiazole, pyridine, pyradine, triazine, pyrimidine, carbazole,azacarbazole, diazacarbazole, indole, benzimidazole, imidazopyridine,and indolysine.

Imidazole, carbazole, indole, indolysine, imidazopyridine, pyridine,pyrimidine and triazine are still more preferable.

As the substituent for Z, a hydrogen atom, a halogen atom (fluorine,chlorine, bromine, or iodine), an alkyl group (e.g. a linear or branchedalkyl having 1 to 6 carbon atoms such as methyl and ethyl; a cycloalkylgroup having 5 to 8 carbon atoms such as cyclopentyl and cyclohexyl), anaralkyl group (e.g. an aralkyl group having 7 to 13 carbon atoms such asbenzyl and phenethyl), an alkenyl group (e.g. a linear or branchedalkenyl group having 2 to 7 carbon atoms such as vinyl and allyl), acyano group, an amino group, in particular a tertiary amino group (e.g.a dialkylamino group having a linear or branched alkyl group having 2 to20 carbon atoms such as diethylamino and diisopropylamino; a diarylaminogroup such as diphenylamino and phenylnaphthylamino; an arylalkylaminogroup having 7 to 20 carbon atoms such as methylphenylamino), an acylgroup (e.g. a linear, branched or cyclic acyl group having a hydrocarbongroup part having 1 to 20 carbon atoms such as acetyl, propionyl,benzoyl, naphthoyl), an alkoxycarbonyl group (e.g. a linear or branchedalkoxycarbonyl group having 2 to 7 carbon atoms such as methoxycarbonyland ethoxycarbonyl), a carboxy group, an alkoxy group (e.g. a linear orbranched alkoxy group having 1 to 6 carbon atoms such as methoxy andethoxy), an aryloxy group (e.g. an aryloxy group having 6 to 10 carbonatoms such as phenoxy and benzyloxy), an alkylsulfonyl group (e.g. analklysulfonyl group having 1 to 6 carbon atoms such as methylsulfonyl,ethylsulfonyl, propylsulfonyl, butylsulfonyl, and hexysulfonyl), ahydroxy group, an amide group (an alklylamide group having 2 to 7 carbonatoms such as methylamide, dimethylamide, and diethylamide; an arylamidegroup such as benzylamide and dibenzylamide), an aromatic hydrocarbonring group (e.g. an aromatic hydrocarbon ring group formed of amonocyclic or condensed benzene ring containing two to four rings suchas phenyl, naphthyl, anthryl, phenanthryl, and pyrenyl), or an aromaticheterocyclic group (e.g. an aromatic heterocyclic group formed of a 5-or 6-membered monocyclic or condensed ring containing two to three ringssuch as carbazolyl, pyridyl, triazyl, pyrazyl, quinoxalyl, and thienyl).

More preferred examples of the substituent for Z include a hydrogenatom, a halogen atom, an alkyl group, an alkoxy group, an aromatichydrocarbon ring group, and an aromatic heterocyclic group.

The above-mentioned substituent may further have a substituent. Examplesof such substituent include a halogen atom (fluorine, chlorine, bromine,or iodine), an alkyl group (e.g. a linear or branched alkyl group having1 to 6 carbon atoms such as methyl and ethyl), an alkenyl group (e.g. alinear or branched alkenyl group having 1 to 6 carbon atoms such asvinyl and allyl), an alkoxycarbonyl group (e.g. a linear or branchedalkoxycarbonyl group having 1 to 6 carbon atoms such as methoxycarbonyland ethoxycarbonyl), an alkoxy group (e.g. a linear or branched alkoxygroup having 1 to 6 carbon atoms such as methoxy and ethoxy), an aryloxygroup (e.g. an aryloxy group having 6 to 10 carbon atoms such as phenoxyand naphthoxy), a dialkylamino group (e.g. a dialkylamino group having alinear or branched alkyl group having 2 to 20 carbon atoms such asdiethylamino and diisopropylamino), a diarylamino group (e.g. adiarylamino group such as diphenylamino and phenylnaphthylamino), anaromatic hydrocarbon ring group (e.g. an aromatic hydrocarbon ring groupsuch as phenyl), an aromatic heterocyclic group (e.g. an aromaticheterocyclic group formed of a 5- or 6-membered monocyclic ring such asthienyl and pyridyl), an acyl group (e.g. a linear or branched acylgroup having 1 to 6 carbon atoms such as acetyl and propionyl), ahaloalkyl group (e.g. a linear or branched haloalkyl group having 1 to 6carbon atoms such as trifluoromethyl), and a cyano group. Of these, ahalogen atom, an alkoxy group, and an aromatic hydrocarbon ring groupare more preferable.

In the formula (1), L₁ represents a linking group formed by bonding 1 to4 divalent aromatic groups which each may have a substituent. L₁ ispreferably —Ar¹—Ar^(2′)—Ar^(3′)—, —Ar^(4′)—Ar^(5′)—Ar^(6′)—, or—Ar^(7′)—Ar^(8′)—Ar^(9′)—Ar^(10′)—. Ar^(1′), Ar^(2′), Ar^(3′), Ar^(4′),Ar^(6′), Ar^(7′) and Ar^(10′) are independently a divalent group formedof a 5- or 6-membered monocyclic or condensed aromatic ring containingtwo to five rings, which may be substituted. Ar^(5′), Ar^(8′) andAr^(9′) are independently a divalent group formed of a 5- or 6-memberedmonocyclic or condensed aromatic ring containing two to five rings,which may be substituted, or —NAr^(11′)— (Ar^(11′) is a monovalentaromatic hydrocarbon ring group or an aromatic heterocyclic group whichmay have a substitutent).

Specific examples of Ar^(1′), Ar^(2′), Ar^(3′), Ar^(4′), Ar^(6′),Ar^(7′) and Ar^(10′) include a divalent aromatic ring group such asphenylene, naphthylene, anthrylene, phenanthrylene, pyrenylene,perilenylene, and a divalent aromatic heterocyclic group suchaspyridylene, triazylene, pyrazylene, quinoxalene, thienylene, andoxadiazolylene.

Ar^(5′), Ar^(8′) and Ar^(9′) are divalent aromatic groups represented bythe groups mentioned above as Ar^(1′) or the like, or a divalentarylamine group represented by —NAr^(11′)— (where Ar^(11′) represents amonovalent aromatic hydrocarbon ring group or an aromatic heterocyclicgroup which may have a substituent). Examples of Ar^(11′) include a 5-or 6-membered aromatic group, such as phenyl, naphthyl, anthryl,phenanthryl, thienyl, pyridyl, and carbazolyl, which each may have asubstituent.

As Ar^(1′), which is the smallest linking group as L₁, it is preferredthat Ar^(1′) be a condensed ring containing three or more rings toimprove the strength of the compound as well as the heat resistance ofthe compound derived therefrom.

It is preferred that Ar^(2′), Ar^(3′), Ar^(4′), Ar^(6′), Ar^(7′) andAr^(10′) be a monocyclic or condensed ring containing two to threerings, more preferably a monocyclic or condensed ring containing tworings.

In order to improve heat resistance, Ar^(5′), Ar^(8′) and Ar^(9′) arepreferably an aromatic ring. In respect of improving amorphous propertyof the compound, Ar^(5′), Ar^(8′) and Ar^(9′) are preferably—NAr^(11′)—. When Ar^(5′), Ar^(8′) and Ar^(9′) are —NAr^(11′)—, theemission wavelength of the compound can be shifted to a longerwavelength region to obtain a desired emission wavelength readily. Ifone of Ar^(8′) and Ar^(9′) is —NAr^(11′)—, it is preferred that theremaining be an aromatic group.

As the substituent for Ar^(1′) to Ar^(10′), the same substituent asthose exemplified as the substituent for Z can be given, for example. Ofthese, an alkyl group, an alkoxy group, an aromatic hydrocarbon ringgroup or an aromatic heterocyclic group are preferable.

As the substituent for Ar^(11′), the same substituent as thoseexemplified for Z can be given, for example. Of these, an arylaminogroup, an aromatic hydrocarbon ring group such as phenyl and naphthyl,and an aromatic heterocyclic group such as carbazolyl group areparticularly preferable.

Ar¹ and Ar² in the formula (1) are independently an aromatic hydrocarbonring group or an aromatic heterocyclic group, which may have asubstituent. As the aromatic hydrocarbon ring group represented by Ar¹and Ar², a monocyclic or condensed benzene ring containing two to fiverings can be given, for example. Specific examples include phenyl,naphthyl, anthryl, phenathryl, pyrenyl, and perilenyl. As the aromaticheterocyclic group, a 5- or 6-membered monocyclic or condensed ringcontaining two to five rings can be given. Specific examples includepyridyl, triazinyl, pyradinyl, quinoxalynyl, and thienyl.

Examples of the substituent for the aromatic hydrocarbon ring group orthe aromatic heterocyclic group include an alkyl group (e.g. a linear orbranched alkyl group having 1 to 6 carbon atoms such as methyl andethyl), an alkenyl group (e.g. a linear or branched alkenyl group having1 to 6 carbon atoms such as vinyl and allyl), an alkoxycarbonyl group(e.g. a linear or branched alkoxycarbonyl group having 1 to 6 carbonatoms such as methoxycarbonyl and ethoxycarbonyl), an alkoxy group (alinear or branched alkoxy group having 1 to 6 carbon atoms such asmethoxy and ethoxy), an aryloxy group (e.g. an aryloxy group having 6 to10 carbon atoms such as phenoxy and naphthoxy), an aralkyloxy group(e.g. aryloxy group having 7 to 13 carbon atoms such as benzyloxy), asecondary or tertiary amino group (e.g. a dialkylamino group having alinear or branched alkyl group having 2 to 20 carbon atoms such asdiethylamino and diisopropylamino; a diarylamino group such asdiphenylamino and phenylnaphthylamino, an arylalkylamino group having 7to 20 carbon atoms such as methylphenylamino), a halogen atom (fluorine,chlorine, bromine, or iodine), an aromatic hydrocarbon ring group (e.g.an aromatic hydrocarbon ring group having 6 to 10 carbon atoms such asphenyl and naphthyl), and an aromatic heterocyclic group (e.g. anaromatic heterocyclic group formed of a 5- or 6-membered monocyclic orcondensed ring containing two rings such as thienyl and pyridyl).

Of these, an alkyl group, an alkoxy group, an alkylamino group, anarylamino group, an arylalkylamino group, a halogen atom, an aromatichydrocarbon ring group, and an aromatic heterocyclic group arepreferable. In particular, an alkyl group, an alkoxy group, and anarylamino group are preferable.

If Ar¹ and Ar² have a structure in which three or more aromatic groupsare connected in series through two or more direct linkages, like aterphenyl group, the hole-transporting property inherent to an arylaminogroup represented by —NAr¹Ar² may deteriorate, and the glass transitiontemperature (Tg) of the compound may lower.

Therefore, in order not to impair the property of the compound of theinvention, it is important that both of Ar¹ and Ar² be a group in whichthree or more aromatic groups are not connected in series through adirect linkage or short, chain-like linking group.

A preferred nitrogen-containing compound represented by the formula (1)is a carbazole derivative represented by the following formula (6).

In the formula (6), Cz is a substituted or unsubstituted carbazolylgroup.

Examples of the carbazolyl group represented by Cz include 1-carbazolyl,2-carbazolyl, 3-carbazolyl, 4-carbazolyl, and N-carbazolyl. Preferably,2-carbazolyl, 3-carbozolyl, and N-carbazolyl.

These carbozolyl groups may have a substituent. As such a substituent,the same substituent as those exemplified as the substituent for Z orthe like in the formula (1) can be given.

In the formula (6), L₃ represents a linking group which may be formed bybonding of 1 to 4 divalent aromatic groups, which each may have asubstituent. Preferred groups as L₃ are the same as those for L₁ in theformula (1).

In the formula (6), Ar₁₅ and Ar₁₆ are independently an aromatichydrocarbon ring group or an aromatic heterocyclic group, which may havea substituent. Preferred groups as Ar₁₅ and Ar₁₆ are the same as thosefor Ar₁ and Ar₂ in the formula (1).

The carbazolyl derivative in the formula (6) is preferably a compoundcontaining an N-carbazolyl group represented by the following formula(7).

wherein Ar₁₇ and Ar₁₈ are independently an aromatic hydrocarbon ringgroup or an aromatic heterocyclic group which may have a substituent; anR₆ to R₁₃ are independently a hydrogen atom, a halogen atom, an alkylgroup, an aralkyl group, an alkenyl group, a cyano group, an aminogroup, an acyl group, an alkoxycarbonyl group, a carboxyl group, analkoxy group, an aryloxy group, an alkylsulfonyl group, a hydroxy group,an amide group, an aromatic hydrocarbon ring group or an aromaticheterocyclic group, which may further be substituted; adjacent atoms orgroups represented by R₆ to R₁₃ may forma ring; and L₄ is a linkinggroup formed by bonding of 1 to 4 divalent aromatic groups which eachmay have a substituent.

In the formula (7), the examples of the groups represented by R⁶ to R¹³are the same as those exemplified above for Z.

Adjacent atoms or groups represented by R⁶ to R¹³ may be bonded eachother to form a ring which is condensed to the N-carbazolyl group. Thering formed by bonding of the adjacent atoms or groups is normally a 5-to 8-membered ring, preferably a 5- or 6-membered ring, more preferablya 6-membered ring. This ring may either be an aromatic ring or anon-aromatic ring, but preferably an aromatic ring. The ring may beeither an aromatic hydrocarbon ring or an aromatic heterocyclic ring,but preferably an aromatic hydrocarbon ring.

In the N-carbazolyl group in the formula (7), examples of the condensedring which is formed by bonding of any of R⁶ to R¹³ to bond to theN-carbozolyl group are given below.

It is particularly preferred that all of R⁶ to R¹³ be a hydrogen atom(in other words, the N-carbozolyl group is unsubstituted).Alternatively, one or more of R⁶ to R¹³ are any of methyl, phenyl andmethoxy, and the remaining is a hydrogen atom.

It is particularly preferred that the compound represented by theformula (7) is a compound represented by the following formula (8).

Examples of R⁶ to R¹⁵ are the same as those exemplified as thesubstitutent for Z. R⁶ to R¹⁵ may be bonded to each other to form asaturated or unsaturated ring. Ar₁₉ and Ar₂₀ are independently anaromatic hydrocarbon ring group or an aromatic heterocyclic group, whichmay have a substitutent. Examples of R⁶ to R¹⁵ are the same as those forAr₁ as mentioned above.

The fluorene-based compound represented by the formula (9) may also bepreferably employed.

wherein X₁ is an N-carbazoyl group which is unsubstituted or mono- orpoly-substituted by a halogen atom, an alkyl group having 1 to 10 carbonatoms, an alkoxy group having 1 to 10 carbon atoms or an aryl grouphaving 6 to 10 carbon atoms, an N-phenoxazyl group which isunsubstituted or mono- or poly-substituted by a halogen atom, an alkylgroup having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbonatoms, or an aryl group having 6 to 10 carbon atoms, or anN-phenothiazyl group which is unsubstituted or mono- or poly-substitutedby a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxygroup having 1 to 10 carbon atoms, or an aryl group having 6 to 10carbon atoms; X₂ is an N-carbazoyl group which is unsubstituted or mono-or poly-substituted by a halogen atom, an alkyl group having 1 to 10carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an arylgroup having 6 to 10 carbon atoms, an N-phenoxazyl group which isunsubstituted or mono- or poly-substituted by a halogen atom, an alkylgroup having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbonatoms, or an aryl group having 6 to 10 carbon atoms, an N-phenothiazylgroup which is unsubstituted or mono- or poly-substituted by a halogenatom, an alkyl group having 1 to 10 alkyl groups, an alkoxy group having1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, or—NAr^(21′)Ar^(22′) (wherein Ar^(21′) and Ar^(22′) are a carbocyclicaromatic group having 6 to 20 total carbon atoms or a heterocyclicaromatic group having 3 to 20 total carbon atoms which is unsubstitutedor mono- or poly-substituted by a halogen atom, an alkyl group, analkoxy group, or an aryl group.

B₁ and B₂ are a hydrogen atom, a linear, branched or cyclic alkyl group,a carbocyclic aromatic group having 6 to 20 total carbon atoms or aheterocyclic aromatic group having 3 to 20 total carbon atoms, which isunsubstituted or mono- or poly-substituted by a halogen atom, an alkylgroup, an alkoxy group, or an aryl group, or an aralkyl group which issubstituted or mono- or poly-substituted by a halogen atom, an alkylgroup, an alkoxy group, or an aryl group or an aralkyl group which isunsubstituted or mono- or poly-substituted by a halogen atom, an alkylgroup, an alkoxy group or an aryl group; and Z₁ and Z₂ are a hydrogenatom, a halogen atom, a linear, branched or cyclic alkyl group, alinear, branched or cyclic alkoxy group, or a carbocyclic aromatic grouphaving 6 to 20 total carbon atoms or a heterocyclic aromatic grouphaving 3 to 20 total carbon atoms, which is unsubstituted or mono- orpoly-substituted by a halogen atom, an alkyl group, an alkoxy group, oran aryl group.

In the compound represented by the formula (9), X₁ is a substituted orunsubstituted N-carbozoyl group, a substituted or unsubstitutedN-phenoxazyl group, or a substituted or unsubstituted N-phenothiazylgroup. Preferably, X₁ is an N-carbozoyl group, an N-phenoxazyl group oran N-phenothiazyl group which is unsubstituted or mono- orpoly-substituted by a halogen atom, an alkyl group having 1 to 10 carbonatoms, an alkoxy group having 1 to 10 carbon atoms, or an aryl grouphaving 6 to 10 carbon atoms. More preferably, X₁ is an N-carbozoylgroup, an N-phenoxazyl group or an N-phenothiazyl group which isunsubstituted or mono- or poly-substituted by a halogen atom, an alkylgroup having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbonatoms, or an aryl group having 6 to 10 carbon atoms. Still morepreferably, X₁ is an unsubstituted N-carbazoyl group, an unsubstitutedN-phenoxazyl group or an unsubstituted N-phenothiazyl group.

Specific examples of the substituted or unsubstituted N-carbazoyl group,the substituted or unsubstituted N-phenoxazyl group, and the substitutedor unsubstituted N-phenothiazyl group represented by X₁ includeN-carbazoyl, 2-methyl-N-carbazoyl, 3-methyl-N-carbazoyl,4-methyl-N-carbozoyl, 3-n-butyl-N-carbazoyl, 3-n-hexyl-N-carbazoyl,3-n-octyl-N-carbazoyl, 3-n-decyl-N-carbazoyl, 3,6-dimethyl-N-carbazoyl,2-methoxy-N-carbazoyl, 3-methoxy-N-carbazoyl, 3-ethoxy-N-carbazoyl,3-isopropoxy-N-carbazoyl, 3-n-butoxy-N-carbozoyl,3-n-octyloxy-N-carbozoyl, 3-n-decyloxy-N-carbazoyl,3-phenyl-N-carbazoyl, 3-(4′-methylphenyl)-N-carbazoyl,3-chloro-N-carbazoyl, N-phenoxazyl, N-phenothiazyl, and2-methyl-N-phenothiazyl. In the compound represented by the generalformula (1), X₂ is a substituted or unsubstituted N-carbazoyl group, asubstituted or unsubstituted N-phenoxazyl group, a substituted orunsubstituted N-phenothiazyl group or —NAr^(21′)Ar^(22′) (whereinAr^(21′) and Ar^(22′) are a substituted or unsubstituted aryl group).

As specific examples of the substituted or unsubstituted N-carbazoylgroup, the substituted or unsubstituted N-phenoxazyl group, and thesubstituted or unsubstituted N-phenothiazyl group represented by X₂, thesame N-carbazoyl groups, N-phenoxazyl groups and N-phenothiazyl groupsas those exemplified as the specific examples for X₁ can be given.

In NAr^(21′)Ar^(22′), Ar^(21′) and Ar^(22′) are a substituted orunsubstituted aryl group. Here, the aryl group means a carbocyclicaromatic group such as phenyl, naphthyl, and anthryl or a heterocyclicaromatic group such as furyl, thienyl and pyridyl. Ar^(21′) and Ar^(22′)are preferably a carbocyclic aromatic group having 6 to 20 total carbonatoms or a heterocyclic aromatic group having 3 to 20 total carbonatoms, which is unsubstituted or mono- or poly-substituted by a halogenatom, an alkyl group, an alkoxy group or an aryl group. More preferably,Ar^(21′) and Ar^(22′) are a carbocyclic aromatic group having 6 to 20total carbon atoms, which is unsubstituted or mono- or poly-substitutedby a halogen atom, an alkyl group having 1 to 14 carbon atoms, an alkoxygroup having 1 to 14 carbon atoms or an aryl group having 6 to 10 carbonatoms. Still more preferably, Ar^(21′) and Ar^(22′) are a carbocyclicaromatic group having 6 to 16 total carbon atoms, which is unsubstitutedor mono- or poly-substituted by a halogen atom, an alkyl group having 1to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or an arylgroup having 6 to 10 carbon atoms.

Specific examples of Ar^(21′) and Ar^(22′) include, but not limitedthereto, phenyl, 1-naphthyl, 2-naphthyl, 2-anthryl, 9-anthryl,4-quinolyl, 4-pyridyl, 3-pyridyl, 2-pyridyl, 3-furyl, 2-furyl,3-thienyl, 2-thienyl, 2-oxazolyl, 2-thiazolyl, 2-benzoxazolyl,2-benzothiazolyl, 2-benzoimidazolyl, 4-methylphenyl, 3-methylphenyl,2-methylphenyl, 4-ethylphenyl, 3-ethylphenyl, 2-ethylphenyl,4-n-propylphenyl, 4-isopropylphenyl, 2-isopropylphenyl, 4-n-butylphenyl,4-isobutylphenyl, 4-sec-butylphenyl, 2-sec-butylphenyl,4-tert-butylphenyl, 3-tert-butylphenyl, 2-tert-butylphenyl,4-n-pentylphenyl, 4-isopentylphenyl, 2-neopentylphenyl,4-tert-pentylphenyl, 4-n-hexylphenyl, 4-(2′-ethylbutyl)phenyl,4-n-heptylphenyl, 4-n-octylphenyl, 4-(2′-ethylhexyl)phenyl,4-tert-octylphenyl, 4-n-decylphenyl, 4-n-dodecylphenyl,4-n-tetradecylphenyl, 4-cyclopentylphenyl, 4-cyclohexylphenyl,4-(4′-methylcylohexyl)phenyl, 4-(4′-tert-butylcyclohexyl)phenyl,3-cyclohexylphenyl, 2-cyclohexylphenyl, 4-ethyl-1-naphthyl,6-n-butyl-2-naphthyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl,3,4-dimethylphenyl, 3,5-dimethylphenyl, 2,6-dimethylphenyl,2,4-diethylphenyl, 2,3,5-trimethylphenyl, 2,3,6-trimethylphenyl,3,4,5-trimethylphenyl, 2,6-diethylphenyl, 2,5-diisopropylphenyl,2,6-diisobutylphenyl, 2,4-di-tert-butylphenyl, 2,5-di-tert-butylphenyl,4,6-di-tert-butyl-2-methylphenyl, 5-tert-butyl-2-methylphenyl,4-tert-butyl-2,6-dimethylphenyl,

4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl,3-ethoxyphenyl, 2-ethoxyphenyl, 4-n-propoxyphenyl, 3-n-propoxyphenyl,4-isopropoxyphenyl, 2-isopropoxyphenyl, 4-n-butoxyphenyl,4-isobutoxyphenyl, 2-sec-butoxyphenyl, 4-n-pentyloxyphenyl,4-isopentyloxyphenyl, 2-isopentyloxyphenyl, 4-neopentyloxyphenyl,2-neopentyloxyphenyl, 4-n-hexyloxyphenyl, 2-(2′-ethylbutyl)oxyphenyl,4-n-octyloxyphenyl, 4-n-decyloxyphenyl, 4-n-dodecyloxyphenyl,4-n-tetradecyloxyphenyl, 4-cyclohexyloxyphenyl, 2-cyclohexyloxyphenyl,2-methoxy-1-naphthyl, 4-methoxy-1-naphthyl, 4-n-butoxy-1-naphthyl,5-ethoxy-1-naphthyl, 6-methoxy-2-naphthyl, 6-ethoxy-2-naphthyl,6-n-buthoxy-2-naphthyl, 6-n-hexyoxy-2-naphthyl, 7-methoxy-2-naphthyl,7-n-buthoxy-2-naphthyl, 2-methyl-4-methoxyphenyl,2-methyl-5-methoxyphenyl, 3-methyl-5-methoxyphenyl,3-ethyl-5-methoxyphenyl, 2-methoxy-4-methylphenyl,3-methoxy-4-methylphenyl, 2,4-dimethoxyphenyl, 2,5-dimethoxyphenyl,2,6-dimethoxyphenyl, 3,4-dimethoxyphenyl, 3,5-dimethoxyphenyl,3,5-diethoxyphenyl, 3,5-di-n-buthoxyphenyl, 2-methoxy-4-ethoxyphenyl,2-methoxy-6-ethoxyphenyl, 3,4,5-trimethoxyphenyl, 4-phenylphenyl,3-phenylphenyl, 2-phenylphenyl, 4-(4′-methylphenyl)phenyl,4-(3′-methylphenyl)phenyl, 4-(4′-methoxyphenyl)phenyl,4-(4′-n-buthoxyphenyl)phenyl, 2-(2′-methoxyphenyl)phenyl,4-(4′-chlorophenyl)phenyl, 3-methyl-4-phenylphenyl,3-methoxy-4-phenylphenyl,

4-fluorophenyl, 3-fluorophenyl, 2-fluorophenyl, 4-chlorophenyl,3-chlorophenyl, 2-chlorophenyl, 4-bromophenyl, 2-bromophenyl,4-chloro-1-naphthyl, 4-chloro-2-naphthyl, 6-bromo-2-naphthyl,2,3-difluorophenyl, 2,4-difluorophenyl, 2,5-difluorophenyl,2,6-difluorophenyl, 3,4-difluorophenyl, 3,5-difluorophenyl,2,3-dichlorophenyl, 2,4-dichlorophenyl, 2,5-dichlorophenyl,3,4-dichlorophenyl, 3,5-dichlorophenyl, 2,5-dibromophenyl,2,4,6-trichlorophenyl, 2,4-dichloro-1-naphthyl, 1,6-dichloro-2-naphthyl,2-fluoro-4-methylphenyl, 2-fluoro-5-methylphenyl,3-fluoro-2-methylphenyl, 3-fluoro-4-methylphenyl,2-methyl-4-fluorophenyl, 2-methyl-5-fluorophenyl,3-methyl-4-fluorophenyl, 2-chloro-4-methylphenyl,2-chloro-5-methylphenyl, 2-chloro-6-methylphenyl,2-methyl-3-chlorophenyl, 2-methyl-4-chlorophenyl,3-methyl-4-chlorophenyl, 2-chloro-4,6-dimethylphenyl,2-methoxy-4-fluorophenyl, 2-fluoro-4-methoxyphenyl,2-fluoro-4-ethoxyphenyl, 2-fluoro-6-methoxyphenyl,3-fluoro-4-ethoxyphenyl, 3-chloro-4-methoxyphenyl,2-methoxy-5-chlorophenyl, 3-methoxy-6-chlorophenyl, and5-chloro-2,4-dimethoxyphenyl.

In the compound represented by the formula (9), B₁ and B₂ are a hydrogenatom, a linear, branched or cyclic alkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted aralkylgroup. Preferably, B₁ and B₂ are a hydrogen atom, a linear, branched orcyclic alkyl group having 1 to 16 carbon atoms, a substituted orunsubstituted aryl group having 4 to 16 carbon atoms, or a substitutedor unsubstituted aralkyl group having 5 to 16 carbon atoms. Morepreferably, B₁ and B₂ are a hydrogen atom, a linear, branched or cyclicalkyl group having 1 to 8 carbon atom, a substituted or unsubstitutedaryl group having 6 to 12 carbon atoms or a substituted or unsubstitutedaralkyl group having 7 to 12 carbon atoms. Still more preferably, B₁ andB₂ are a linear, branched or cyclic alkyl group having 1 to 8 carbonatoms, a carbocyclic aromatic group having 6 to 10 carbon atoms, and acarbocyclic aralkyl group having 7 to 10 carbon atoms.

As the specific examples of the substituted or unsubstituted aryl grouprepresented by B₁ and B₂, the same substituted or unsubstituted arylgroup exemplified as the specific examples for Ar₁ and Ar₂ can be given,for example. Specific examples of the liner, branched or cyclic alkylgroup represented by B₁ and B₂ include, but not limited thereto, methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl,n-pentyl, iso-pentyl, neo-pentyl, tert-pentyl, cyclopentyl, n-hexyl,2-ethylbutyl, 3,3-dimethylbutyl, cyclohexyl, n-heptyl, cyclohexylmethyl,n-octyl, tert-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-dodecyl,n-tetradecyl and n-hexadecyl.

Specific examples of the substituted or unsubstituted aralkyl grouprepresented by B₁ and B₂ include, but not limited thereto, an aralkylgroup such as benzyl, phenethyl, α-methylbenzyl, α,α-dimethylbenzyl,1-naphthylmethyl, 2-naphthylmethyl, furfuryl, 2-methylbenzyl,3-methylbenzyl, 4-methylbenzyl, 4-ethylbenzyl, 4-isopropylbenzyl,4-tert-butylbenzyl, 4-n-hexylbenzyl, 4-nonylbenzyl, 3,4-dimethylbenzyl,3-methoxybenzyl, 4-methoxybenzyl, 4-ethoxybenzyl, 4-n-butoxybenzyl,4-n-hexyloxybenzyl, 4-nonyloxybenzyl, 4-fluorobenzyl, 3-fluorobenzyl,2-chlorobenzyl, and 4-chlorobenzyl.

Z₁ and Z₂ are a hydrogen atom, a halogen atom, a linear, branched orcyclic alkyl group, a linear, branched or cyclic alkoxy group, or asubstituted or unsubstituted aryl group. Preferably, Z₁ and Z₂ are ahydrogen atom, a halogen atom, a linear, branched or cyclic alkyl grouphaving 1 to 16 carbon atoms, a linear, branched or cyclic alkoxy grouphaving 1 to 16 carbon atoms, or a substituted or unsubstituted arylgroup having 4 to 20 carbon atoms. More preferably, Z₁ and Z₂ are ahydrogen atom, a halogen atom, a linear, branched or cyclic alkyl grouphaving 1 to 8 carbon atoms, a linear, branched or cyclic alkoxy grouphaving 1 to 8 carbon atoms, or a substituted or unsubstituted aryl grouphaving 6 to 12 carbon atoms. Still more preferably, Z₁ and Z₂ are ahydrogen atom.

As the specific examples of the linear, branched or cyclic alkyl grouprepresented by Z₁ and Z₂, the same linear, branched or cyclic alkylgroup exemplified as the specific examples for B₁ and B₂ can be given.As the specific examples of the substituted or unsubstituted aryl grouprepresented by Z₁ and Z₂, the same substituted or unsubstituted arylgroup exemplified as the specific examples for Ar^(21′) and Ar^(22′) canbe given, for example.

Specific examples of the halogen atom, the linear, branched or cyclicalkoxy group represented by Z₁ and Z₂ include a halogen atom such asfluorine, chlorine, and bromine, and an alkoxy group such as methoxy,ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy,n-pentyloxy, isopentyloxy, neopentyloxy, cyclopentyloxy, n-hexyloxy,2-ethylbutoxy, 3,3-dimethylbutoxy, cyclohexyloxy, n-heptyloxy,cyclohexylmethyloxy, n-octyloxy, 2-ethylhexyloxy, n-nonyloxy,n-decyloxy, n-dodecyloxy, n-tetradecyloxy, and n-hexadecyloxy.

Specific examples of the compound represented by the above formula (9)include, but not limited thereto, the following compounds (No. 1-100).

Example Compounds

-   1. 7-(N′-carbazoyl)-N,N-diphenyl-9H-fluorene-2-amine-   2.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methylphenyl)-9-methyl-9H-fluorene-2-amine-   3. 7-(N′-carbazoyl)-N,N-diphenyl-9,9-dimethyl-9H-fluorene amine-   4.    7-(N′-carbazoyl)-N-phenyl-N-(3′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   5.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   6.    7-(N′-carbazoyl)-N-phenyl-N-(4′-ethylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   7.    7-(N′-carbazoyl)-N-phenyl-N-(4′-tert-butylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   8.    7-(N′-carbazoyl)-N-phenyl-N-(3′,4′-dimethylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   9.    7-(N′-carbazoyl)-N-phenyl-N-(3′,5′-dimethylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   10.    7-(N′-carbazoyl)-N,N-di(3′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   11.    7-(N′-carbazoyl)-N,N-di(4′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   12.    7-(N′-carbazoyl)-N,N-di(4′-ethylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   13.    7-(N′-carbazoyl)-N-phenyl-N-(3′-methoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   14.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   15.    7-(N′-carbazoyl)-N-phenyl-N-(4′-ethoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   16.    7-(N′-carbazoyl)-N-phenyl-N-(4′-n-butoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   17.    7-(N′-carbazoyl)-N,N-di(4′-methoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   18.    7-(N′-carbazoyl)-N-(3′-methylphenyl)-N-(4″-methoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   19.    7-(N′-carbazoyl)-N-(4′-methylphenyl)-N-(4″-methoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   20.    7-(N′-carbazoyl)-N-phenyl-N-(3′-fluorophenyl)-9,9-dimethyl-9H-fluorene-2-amine-   21.    7-(N′-carbazoyl)-N-phenyl-N-(4′-chlorophenyl)-9,9-dimethyl-9H-fluorene-2-amine-   22.    7-(N′-carbazoyl)-N-phenyl-N-(4′-phenylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   23.    7-(N′-carbazoyl)-N-phenyl-N-(1′-naphthyl)-9,9-dimethyl-9H-fluorene-2-amine-   24.    7-(N′-carbazoyl)-N-phenyl-N-(2′-naphthyl)-9,9-dimethyl-9H-fluorene-2-amine-   25.    7-(N′-carbazoyl)-N-(4′-methylphenyl)-N-(2″-naphthyl)-9,9-dimethyl-9H-fluorene-2-amine-   26.    7-(N′-carbazoyl)-N-phenyl-N-(2′-furyl)-9,9-dimethyl-9H-fluorene-2-amine-   27.    7-(N′-carbozyl)-N-phenyl-N-(2′-thienyl)-9,9-dimethyl-9H-fluorene-2-amine-   28.    7-(N′-carbazoyl)-N,N-diphenyl-4-fluoro-9,9-dimethyl-9H-fluorene-2-amine-   29.    7-(N′-carbazoyl)-N,N-diphenyl-3-methoxy-9,9-dimethyl-9H-fluorene-2-amine-   30.    7-(N′-carbazoyl)-N,N-diphenyl-4-phenyl-9,9-dimethyl-9H-fluorene-2-amine-   31.    7-(3‘-methyl-N’-carbazoyl)-N,N-diphenyl-9,9-dimethyl-9H-fluorene-2-amine-   32.    7-(3‘-methoxy-N’-carbazoyl)-N,N-diphenyl-9,9-dimethyl-9H-fluorene-2-amine-   33.    7-(3‘-chloro-N’-carbazoyl)-N,N-diphenyl-9,9-dimethyl-9H-fluorene-2-amine-   34. 2,7-di(N-carbazoyl)-9,9-dimethyl-9H-fluorene-   35. 7-(N′-phenoxazyl)-N,N-diphenyl-9,9-dimethyl-9H-fluorene-2-amine-   36.    7-(N′-phenoxazyl)-N,N-di(4′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   37. 2,7-di(N-phenoxazyl)-9,9-dimethyl-9H-fluorene-   38.    7-(N′-phenothiazyl)-N,N-diphenyl-9,9-dimethyl-9H-fluorene-2-amine-   39.    7-(N′-phenothiazyl)-N-phenyl-N-(3′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   40.    7-(N′-phenothiazyl)-N-phenyl-N-(4′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   41.    7-(N′-phenothiazyl)-N,N-di(4′-methylphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   42.    7-(N′-phenothiazyl)-N-phenyl-N-(4′-methoxyphenyl)-9,9-dimethyl-9H-fluorene-2-amine-   43.    7-(N′-phenothiazyl)-N-phenyl-N-(2′-naphthyl)-9,9-dimethyl-9H-fluorene-2-amine-   44. 2,7-di(N-phenothiazyl)-9,9-dimethyl-9H-fluorene-   45. 7-(N′-carbazoyl)-N,N-diphenyl-9,9-diethyl-9H-fluorene-2-amine-   46.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methylphenyl)-9,9-diethyl-9H-fluorene-2-amine-   47.    7-(N′-carbazoyl)-N,N-di(4′-methylphenyl)-9,9-diethyl-9H-fluorene-2-amine-   48.    7-(N′-carbozoyl)-N-phenyl-N-(3′-methoxyphenyl)-9,9-diethyl-9H-fluorene-2-amine-   49.    7-(N′-carbazoyl)-N,N-diphenyl-4-methyl-9,9-diethyl-9H-fluorene-2-amine-   50. 7-(N′-carbazoyl)-N,N-diphenyl-9-isopropyl-9H-fluorene-2-amine-   51.    7-(N′-carbazoyl)-N,N-diphenyl-9,9-di-n-propyl-9H-fluorene-2-amine-   52.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methylphenyl)-9,9-di-n-propyl-9H-fluorene-2-amine-   53.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methoxyphenyl)-9-di-n-propyl-9H-fluorene-2-amine-   54. 2,7-di(N-carbazoyl)-9,9-di-n-propyl-9H-fluorene-   55. 2,7-di(N-phenoxazyl)-9,9-di-n-propyl-9H-fluorene-   56. 7-(N′-carbazoyl)-N,N-diphenyl-9,9-di-n-butyl-9H-fluorene-2-amine-   57.    7-(N′-carbazoyl)-N,N-di(4′-methylphenyl)-9,9-di-n-butyl-9H-fluorene-2-amine-   58. 2,7-di(N′-carbazoyl)-9,9-di-n-butyl-9H-fluorene-   59.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methoxyphenyl)-9,9-di-n-pentyl-9H-fluorene-2-amine-   60.    7-(N′-phenoxazyl)-N-phenyl-N-(3′-methoxyphenyl)-9,9-di-n-pentyl-9H-fluorene-2-amine-   61.    7-(N′-carbazoyl)-N,N-di(4″-methoxyphenyl)-9,9-di-n-pentyl-9H-fluorene-2-amine-   62. 2,7-di(N′-carbazoyl)-9,9-di-n-pentyl-9H-fluorene-   63. 7-(N′-carbazoyl)-N,N-diphenyl-9,9-di-n-hexyl-9H-fluorene-2-amine-   64.    7-(N′-carbazoyl)-N,N-di(4′-methylphenyl)-9,9-di-n-hexyl-9H-fluorene-2-amine-   65. 7-(N′-carbazoyl)-N,N-diphenyl-9-cyclohexyl-9H-fluorene-2-amine-   66. 7-(N′-carbazoyl)-N,N-diphenyl-9,9-di-n-octyl-9H-fluorene-2-amine-   67.    7-(N′-phenoxazyl)-N,N-di(4′-methylphenyl)-9,9-di-n-octyl-9H-fluorene-2-amine-   68.    7-(N′-carbazoyl)-N,N-diphenyl-9-methyl-9-ethyl-9H-fluorene-2-amine-   69.    7-(N′-carbazoyl)-N,N-diphenyl-9-methyl-9-n-propyl-9H-fluorene-2-amine-   70.    7-(N′-phenothiazyl)-N,N-diphenyl-9-methyl-9-n-propyl-9H-fluorene-2-amine-   71.    7-(N′-carbazoyl)-N,N-diphenyl-9-ethyl-9-n-hexyl-9H-fluorene-2-amine-   72.    7-(N′-carbazoyl)-N,N-diphenyl-9-ethyl-9-cyclohexyl-9H-fluorene-2-amine-   73. 7-(N′-carbazoyl)-N,N-diphenyl-9-benzyl-9H-fluorene-2-amine-   74. 7-(N′-carbazoyl)-N,N-diphenyl-9,9-dibenzyl-9H-fluorene-2-amine-   75.    7-(N′-carbazoyl)-N,N-diphenyl-9,9-di(4′-methylbenzyl)-9H-fluorene-2-amine-   76.    7-(N′-carbazoyl)-N,N-diphenyl-9,9-di(4′-methoxybenzyl)-9H-fluorene-2-amine-   77.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methylphenyl)-9,9-dibenzyl-9H-fluorene-2-amine-   78.    7-(N′-carbazoyl)-N,N-di(4′-methylphenyl)-9,9-dibenzyl-9H-fluorene-2-amine-   79.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methoxyphenyl)-9,9-dibenzyl-9H-fluorene-2-amine-   80.    7-(N′-carbazoyl)-N-phenyl-N-(4′-phenylphenyl)-9,9-dibenzyl-9H-fluorene-2-amine-   81.    7-(N′-carbazoyl)-N-phenyl-N-(2′-naphthyl)-9,9-dibenzyl-9H-fluorene-2-amine-   82.    7-(N′-phenoxazyl)-N-phenyl-N-(4′-methylphenyl)-9,9-dibenzyl-9H-fluorene-2-amine-   83.    7-(N′-phenothiazyl)-N,N-di(4′-methylphenyl)-9,9-dibenzyl-9H-fluorene-2-amine-   84. 2,7-di(N-carbazoyl)-9,9-dibenzyl-9H-fluorene-   85. 2,7-di(N-carbazoyl)-9,9-di(4′-methylbenzyl)-9H-fluorene-   86. 2-(N-carbazoyl)-7-(N′-phenothiazyl)-9,9-dibenzyl-9H-fluorene-   87.    7-(N′-carbazoyl)-N,N-diphenyl-9-methyl-9-benzyl-9H-fluorene-2-amine-   88.    7-(N′-phenoxazyl)-N,N-diphenyl-9-ethyl-9-benzyl-9H-fluorene-2-amine-   89. 7-(N′-carbazoyl)-N,N-diphenyl-9,9-diphenyl-9H-fluorene-2-amine-   90.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methylphenyl)-9,9-diphenyl-9H-fluorene-2-amine-   91.    7-(N′-carbazoyl)-N,N-di(4′-methylphenyl)-9,9-diphenyl-9H-fluorene-2-amine-   92.    7-(N′-carbazoyl)-N-phenyl-N-(3′-methylphenyl)-9,9-di(4″-methylphenyl)-9H-fluorene-2-amine-   93.    7-(N′-carbazoyl)-N-phenyl-N-(3′-methylphenyl)-9,9-di(4″-methoxyphenyl)-9H-fluorene-2-amine-   94.    7-(N′-phenoxazyl)-N,N-di(4′-methylphenyl)-9,9-diphenyl-9H-fluorene-2-amine-   95.    7-(N′-phenothiazyl)-N,N-diphenyl-9,9-diphenyl-9H-fluorene-2-amine-   96. 2,7-di(N′-carbazoyl)-9,9-di(4′-methylphenyl)-9H-fluorene-   97. 2-(N-carbazolyl)-7-(N′-phenoxazyl)-9,9-diphenyl-9H-fluorene-   98. 2-(N-phenoxazyl)-7-(N′-phenothiazyl)-9,9-diphenyl-9H-fluorene-   99.    7-(N′-carbazoyl)-N-phenyl-N-(4′-methylphenyl)-9-methyl-9-phenyl-9H-fluorene-2-amine-   100.    7-(N′-carbazoyl)-N,N-diphenyl-9-ethyl-9-phenyl-9H-fluorene-2-amine

Specific examples of the nitrogen-containing heterocyclic derivativewhich can be used in the invention are given below.

In the formula (2), L₂ is a substituted or unsubstituted arylene grouphaving 10 to 40 carbon atoms.

Preferred examples include biphenylene, terphenylene, quarterphenylene,naphthylene, anthracenylene, phenanthyrene, chrysenylene, pyrenylene,fluorenylene, 2,6-diphenylnaphthalene-4′,4″-ene,2-phenylnaphthalene-2,4′-ene, 1-phenylnaphthalene-1,4′-ene,2,7-diphenylfluorenylene-4′,4″-ene, fluorenylene,9,10-diphenylanthracene-4′,4″-ene, and6,12-diphenylchrysenylene-4′,4″-ene.

Biphenylene, terphenylene, fluorenylene, 2-phenylnaphthalene-2,4′-ene,1-phenylnaphthalene-1,4′-ene, and 6,12-diphenylchrysenylene-4′,4″-eneare more preferable.

In the formula (2), Ar₃ to Ar₆ are independently a substituted orunsubstituted aromatic hydrocarbon ring group having 6 to 60 nucleuscarbon atoms, or a substituted or unsubstituted aromatic heterocyclicgroup having 6 to 60 nucleus atoms.

Examples of the substituted or unsubstituted aromatic hydrocarbon ringgroup having 6 to 60 nucleus carbon atoms represented by Ar₃ to Ar₆ inthe formula (2) are the same as those exemplified for Ar₁ and Ar₂ in theformula (1).

As the substituted or unsubstituted aromatic heterocyclic group having 6to 60 nucleus atoms, a 5- or 6-membered monocyclic or condensed ringcontaining two to five rings can be given. Specific examples includepyridyl, triazinyl, pyradinyl, quinoxalinyl and thienyl.

The amine derivative represented by the formula (2) is preferably acompound represented by the following formula (3).

In the formula (3), Ar₃ to Ar₆ in the formula (3) are the same as Ar₃ toAr₆ in the formula (2).

In the formula (3), R_(a) represents a substituent. Specific examples ofR_(a) are the same as those exemplified above as the substituent for Zor the like in the formula (1).

n is an integer of 2 to 4, preferably 2 and 3.

The amine derivative represented by the formula (2) is more preferably acompound represented by the following formula (4) or (5).

In the formula, R₁ to R₅ are a substituent. Examples thereof are thesame as those exemplified as those for R_(a) in the formula (3). R₁ andR₂, and R₃ to R₅ may be bonded to each other to form a saturated orunsaturated ring.

In the formula, Ar₇ to Ar₁₄ are independently a substituted orunsubstituted aromatic hydrocarbon ring group having 6 to 60 carbonatoms or a substituted or unsubstituted aromatic heterocyclic grouphaving 6 to 60 nucleus atoms. Specific examples of Ar₇ to Ar₁₄ are thesame as those exemplified above for Ar₁ and Ar₂ in the formula (1).

As specific examples of the substituent for Ar₇ to Ar₁₄ and R₁ to R₅,the same substituent as those exemplified as the substituent for Z orthe like in the formula (1) can be given. As the structure of thesubstituted or unsubstituted ring formed by bonding of R₁ and R₂, thefollowing can be given. The same can be applied when the ring is formedby bonding of R₃ to R₅.

The following structures are preferable.

Further, it is preferred that at least one of Ar₇ to Ar₁₀ in the formula(4) and at least one of Ar₁₁ and Ar₁₄ in the formula (5) be asubstituted or unsubstituted biphenyl group.

Examples of the substituted or unsubstituted biphenyl group include2-biphenyl, 3-biphenyl, 4-biphenyl, p-terphenyl, m-terphenyl,o-terphenyl, 4′-methyl-biphenyl-4-yl, 4′-t-butyl-biphenyl-4-yl,4′-(1-naphthyl)-biphenyl-4-yl, 4′-(2-naphthyl)-biphenyl-4-yl,2-fluorenyl, and 9,9-dimethyl-2-fluorenyl.

Of these, 3-biphenyl, 4-biphenyl, p-terphenyl, m-terphenyl, and9,9-dimethyl-2-fluorenyl are preferable.

The terminal of the substituted or unsubstituted biphenyl group may besubstituted by an arylamino group.

Specific examples of the amine derivative which can be used in theinvention are given below.

In the organic EL device of the invention, it is preferred that, of thelayers provided in the hole-injecting/hole-transporting region, thelayer which is in contact with the anode be a layer containing anacceptor material.

FIG. 2 is a schematic cross-sectional view showing another embodiment ofthe organic EL device according to the invention.

The organic EL device shown in FIG. 2 is the same as the organic ELdevice shown in FIG. 1, except that an acceptor-containing layer 80 isprovided between the anode 10 and the hole-injecting layer 20.

A lower driving voltage can be realized by the provision of theacceptor-containing layer in such a manner that the acceptor-containinglayer 80 is in contact with the anode 10, as shown in FIG. 2.

The acceptor contained in the acceptor-containing layer 80 will beexplained below.

The acceptor is an organic compound which is readily reduced.

The ease to be reduced of the compound may be measured using thereduction potential. In the invention, a compound having a reductionpotential of −0.8 V or more using a saturated calomel electrode (SCE) asthe reference electrode is preferable, and a compound having a reductionpotential greater than the reduction potential (about 0 V) oftetracyanoquinodimethane (TCNQ) is particularly preferable.

An organic compound having an electron-attracting substituent ispreferable as the organic compound which is easily reduced. Specificexamples of the organic compound having an electron-attractingsubstituent include quinoid derivatives, pyrazine derivatives,arylborane derivatives, imide derivatives, and the like can be given.The quinoid derivatives include quinodimethane derivatives, thiopyrandioxide derivatives, thioxanthene dioxide derivatives, and quinonederivatives.

As preferred examples of the quinoid derivatives, compounds of thefollowing formulas (1a) to (1i) can be given. Note that the compounds ofthe formulas (1a) and (1b) are more preferable.

In the formulas (1a) to (1h), R¹ to R⁴⁸ are independently hydrogen,halogen, a fluoroalkyl group, a cyano group, an alkoxy group, an alkylgroup, or an aryl group. Hydrogen and a cyano group are preferable.

As the halogen for R¹ to R⁴⁸, fluorine and chlorine are preferable.

As the fluoroalkyl group for R¹ to R⁴⁸, a trifluoromethyl group and apentafluoroethyl group are preferable.

As the alkoxy group for R¹ to R⁴⁸, a methoxy group, an ethoxy group, aniso-propoxy group, and a tert-butoxy group are preferable.

As the alkyl group for R¹ to R⁴⁸, a methyl group, an ethyl group, apropyl group, an iso-propyl group, a tert-butyl group, and a cyclohexylgroup are preferable.

As the aryl group for R¹ to R⁴⁸, a phenyl group and a naphthyl group arepreferable.

In the formulas (1a) to (1h), X is an electron-attracting group havingone of the structures of the following formulas (j) to (p). Note thatthe structures of the formulas (j), (k), and (l) are preferable.

wherein R⁴⁹ to R⁵² are independently hydrogen, a fluoroalkyl group, analkyl group, an aryl group, or a heterocyclic ring, provided that R⁵⁰and R⁵¹ may form a ring.

The fluoroalkyl group, alkyl group, and aryl group for R⁴⁹ to R⁵² arethe same as those for R¹ to R⁴⁸.

As the heterocyclic ring for R⁴⁹ to R⁵², substituents of the followingformulas are preferable.

When R⁵⁰ and R⁵¹ form a ring, X is preferably a substituent of thefollowing formula.

wherein R^(51′) and R^(52′) are independently a methyl group, an ethylgroup, a propyl group, or a tert-butyl group.

In the formulas (1a) to (1h), Y is —N═ or —CH═.

As specific examples of the quinoid derivatives, the following compoundscan be given.

Compounds of the following formula (2) can be given as examples of thearylborane derivatives.

In the formula (2), Ar₃₁ to Ar₃₃ are independently an aryl group or aheterocyclic ring having an electron-attracting group.

As the aryl group having an electron-attracting group represented byAr₃₁ to Ar₃₃, a pentafluorophenyl group, a heptafluoronaphthyl group,and a pentafluorophenyl group are preferable.

As the heterocyclic ring having an electron-attracting group representedby Ar₃₁ to Ar₃₃, a quinoline ring, a quinoxaline ring, a pyridine ring,a pyrazine ring, and the like are preferable.

As specific examples of the arylborane derivatives, the followingcompounds can be given.

The arylborane derivative is preferably a compound having at least onefluorine as the substituent for the aryl, and particularly preferablytris-β-(pentafluoronaphthyl)borane (PNB).

Compounds of the following formula (3a) can be given as examples of thethiopyran dioxide derivatives, and compounds of the following formula(3b) can be given as examples of the thioxanthene dioxide derivatives.

In the formulas (3a) and (3b), R⁵³ to R⁶⁴ are independently hydrogen,halogen, a fluoroalkyl group, a cyano group, an alkyl group, or an arylgroup. Hydrogen and a cyano group are preferable.

In the formulas (3a) and (3b), X is an electron-attracting group whichis the same as X in the formulas (1a) to (1i). The structures of theformulas (i), (j), and (k) are preferable.

The halogen, fluoroalkyl group, alkyl group, and aryl group representedby R⁵³ to R⁶⁴ are the same as those for R¹ to R⁴⁸.

Specific examples of the thiopyran dioxide derivatives of the formula(3a) and the thioxanthene dioxide derivatives of the formula (3b) aregiven below.

wherein tBu is a t-butyl group.

As the imide derivatives, naphthalenetetracarboxylic acid diimidecompounds and pyromellitic acid diimide compounds are preferable.

Other than those mentioned above, a nitrogen-containing heterocyclicderivative represented by the following formula (4a), which is disclosedin Japanese Patent No. 3571977, can also be used.

wherein R¹²¹ to R¹²⁶ are independently a substituted or unsubstitutedalkyl group, a substituted or unsubstituted aryl group, a substituted orunsubstituted aralkyl group, or a substituted or unsubstitutedheterocyclic group, provided that R¹²¹ to R²⁶ may be the same ordifferent. R¹²¹ and R¹²², R¹²³ and R¹²⁴, R¹²⁵ and R¹²⁶, R¹²¹ and R¹²⁶,R¹²² and R¹²³, and R¹²⁴ and R¹²⁵ may form a condensed ring.

Further, a compound of the following formula (4b), as disclosed in U.S.Patent Publication No. 2004/0113547, can also be used.

wherein R¹³¹ to R¹³⁶ are a substituent, preferably, anelectron-attracting group such as cyano, nitro, sulfonyl, carbonyl,trifluoromethyl, and halogen.

Specific examples of the compounds represented by the formula (4b) areillustrated below. In the following formula, Me and Ph are methyl andphenyl, respectively.

Further, the compounds of the following formula (5a) can be given.

wherein R⁸¹ to R⁸⁸, which may be the same or different, are selectedfrom a group consisting of hydrogen, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted aryl group, a substituted orunsubstituted heterocyclic ring, halogen, a cyano group, a nitro group,an ester group, an amide group, an alkoxy group, a substituted orunsubstituted phenoxy group and an amino group; the adjacent atoms orgroups represented by R⁸¹ to R⁸⁸ may be bonded to each other to form aring structure; X⁸¹ to X⁸⁴ are independently a carbon atom or a nitrogenatom, and n is an integer of 0 or more.

Specific examples of the compounds represented by the formula (5a) aregiven below.

Representative examples of the structure of the organic EL device of theinvention are shown below. The invention is, however, not limited tothese.

(1) Anode/hole-injecting layer/hole-transporting layer/emittinglayer/electron-transporting layer/cathode

(2) Anode/hole-injecting layer/hole-transporting layer/emittinglayer/electron-transporting layer/electron-injecting layer/cathode (FIG.1)

(3) Anode/hole-injecting layer/hole-transporting layer/emittinglayer/electron-transporting layer/insulative layer/cathode

(4) Anode/insulative layer/hole-injecting layer/hole-transportinglayer/emitting layer/electron-transporting layer/electron-injectinglayer/insulative layer/cathode

(5) Anode/acceptor-containing layer/hole-injectinglayer/hole-transporting layer/emitting layer/electron-transportinglayer/electron-injecting layer/cathode (FIG. 2)

The light emitted by the emitting layer may be outcoupled through eitherthe anode or the cathode, or through both.

In the organic EL device, the region between the anode and the cathodemay have a cavity structure; i.e., a structure in which the lightemitted by the emitting layer is reflected between the anode and thecathode. For example, the cathode is formed of a semi-transparent andsemi-reflective material, and the anode has a light-reflective surface.In this case, emission, which is multi-interfered between thelight-reflective surface of the anode and the light-reflective surfaceof the cathode, is outcoupled through the cathode. The optical distancebetween the light-reflective surface of the anode and thelight-reflective surface of the cathode is determined according to thewavelength of light which is desired to be outcoupled. The thickness ofeach layer is determined in such a manner that such an optical distancecan be obtained. In the organic EL device of top-emission type (emissionis outcoupled outside the device without passing through the supportsubstrate), it is possible to improve outcoupling efficiency and controlthe emission spectrum by the active use of such a cavity structure.

Each member of the organic EL device according to the invention isdescribed below.

(Substrate)

The organic EL device of the invention is formed on a transparentsubstrate. The transparent substrate is a substrate for supporting theorganic EL device, and is preferably a flat and smooth substrate havinga transmittance of 50% or more to rays within visible ranges of 400 to700 nm.

Specific examples thereof include glass plates and polymer plates.Examples of the glass plate include soda-lime glass,barium/strontium-containing glass, lead glass, aluminosilicate glass,borosilicate glass, barium borosilicate glass, and quartz. Examples ofthe polymer plate include polycarbonate, acrylic polymer, polyethyleneterephthalate, polyethersulfide, and polysulfone.

In the case of a top-emission type organic EL device in which light isoutcoupled through the side opposite to the substrate, the substrate isnot necessarily transparent.

[Anode]

The anode of the organic thin film EL device plays a role for injectingholes into its hole-transporting layer or emitting layer. The anodeeffectively has a work function of 4.5 eV or more. Specific examples ofthe anode material used in the invention include metals such as aluminum(Al), chlormium (Cr), molybdenum (Mo), tungsten (W), cupper (Cu), silver(Ag) and gold (Au), alloys thereof, and oxides of these metals andalloys. Further, alloys of tin oxide (SnO₂) and antimony (Sb), ITO(indium tin oxide), InZnO (indium zinc oxide), and alloys of zinc oxide(ZnO) and aluminum (Al) may also be used alone or in combination.

In the case where emission from the emitting layer is outcoupled throughthe anode, the transmittance of the anode to the emission is preferablymore than 10%.

In the case where emission from the emitting layer is outcoupled throughthe cathode, it is preferred that the anode be a reflective electrode.In this case, the anode may be of a stacked structure of a first layerimproved in light reflectance and a second layer provided thereon andhaving a light transmissibility and a large work function.

For example, the first layer is formed of an alloy containing aluminumas the main component. The secondary component may be one which containsat least one element which has a relatively small work function ascompared with aluminum. Preferred examples of such secondary componentinclude a lanthanide-series element. The work function of alanthanide-series element is not large. However, presence of such anelement improves stability and hole-injection property of the anode.Besides the lanthanide-series element, an element such as silicon (Si)and cupper (Cu) may be contained as the secondary element.

As for the content of the secondary element in the aluminum alloy layerconstituting the first layer, if the secondary element is Nd, Ni, Ti orthe like, which serves to stabilize aluminum, it is preferred that thetotal content of the secondary element be 10 wt, or less. With thiscontent, the aluminum alloy layer can be kept stable while maintainingthe reflectance in the aluminum alloy layer during the production of theorganic EL device. In addition, working accuracy, chemical stability,and conductivity of the anode, as well as adhesion of the anode to thesubstrate can also be improved.

The second layer may be formed of at least one of an oxide of aluminumalloy, an oxide of molybdenum, an oxide of zirconium, an oxide ofchromium, and an oxide of tanthallium. If the secondary layer is a layerformed of an oxide of an aluminum alloy (including a naturally oxidizedfilm) containing a lanthanide-series element as the secondary element,transmittance of the secondary layer is improved due to hightransmittance of the oxide of the lanthanide-series element. Therefore,a high reflectivity can be maintained on the surface of the first layer.Further, the secondary layer may be a transparent conductive layerformed of ITO or IZO. Such a conductive layer enables electron-injectingproperties of the anode to be improved.

Further, a conductive layer may be provided on the side of the anodewhich is in contact with the substrate in order to improve adhesionbetween the anode and the substrate. Examples of such a conductive layerinclude transparent conductive materials such as ITO and IZO.

If a display formed of the organic EL device is an active matrix typedrive display, the anode is patterned for each pixel, and provided insuch a manner that it is connected to a thin film transistor provided onthe substrate. In this case, an insulative film is provided on the anodesuch that the surface of the anode for each pixel is exposed through anopening of the insulative film.

The anode can be formed by forming these electrode materials into a thinfilm by deposition, sputtering or the like.

The sheet resistance of the anode is preferably several hundreds Ω/□ orless. The film thickness of the anode, which varies depending upon thematerial thereof, is usually from 10 nm to 1 μm, preferably from 10 to200 nm.

[Emitting Layer]

The emitting layer of the organic EL device has the following functionsin combination.

(1) Injection function: function of allowing injection of holes from theanode or hole-injecting/transporting layer and injection of electronsfrom the cathode or electron-injecting/transporting layer uponapplication of an electric field

(2) Transporting function: function of moving injected carriers(electrons and holes) due to the force of an electric field

(3) Emitting function: function of allowing electrons and holes torecombine to emit light

Note that electrons and holes may be injected into the emitting layerwith different degrees, or the transportation capabilities indicated bythe mobility of holes and electrons may differ. It is preferable thatthe emitting layer move either electrons or holes.

As the method of forming the emitting layer, a known method such asdeposition, spin coating, or an LB method may be applied. It ispreferable that the emitting layer be a molecular deposition film.

The term “molecular deposition film” refers to a thin film formed bydepositing a vapor-phase material compound or a film formed bysolidifying a solution-state or liquid-phase material compound. Themolecular deposition film is distinguished from a thin film (molecularaccumulation film) formed using the LB method by the difference inaggregation structure or higher order structure or the difference infunction ascribable to the difference in structure.

The emitting layer may also be formed by dissolving a binder such as aresin and a material compound in a solvent to obtain a solution, andforming a thin film from the solution by spin coating or the like, asdisclosed in JP-A-57-51781.

As the material used for the first emitting layer, a known long-livedluminescent material may be used. It is preferable to use a material ofthe general formula (I) as the luminescent material.

wherein Ar′ is an aromatic ring having 6 to 50 nucleus carbon atoms or aheteroaromatic ring having 5 to 50 nucleus atoms.

As specific examples of Ar′, a phenyl ring, a naphthyl ring, ananthracene ring, a biphenylene ring, an azulene ring, an acenaphthylenering, a fluorene ring, a phenanthrene ring, a fluoranthene ring, anacephenanthrene ring, a triphenylene ring, a pyrene ring, a chrysenering, a benzanthracene ring, a naphthacene ring, a picene ring, aperylene ring, a pentaphene ring, a pentacene ring, a tetraphenylenering, a hexaphene ring, a hexacene ring, a rubicene ring, a coronenering, a trinaphthylene ring, a pyrrole ring, an indole ring, a carbazolering, an imidazole ring, a benzimidazole ring, an oxadizole ring, atriazole ring, a pyridine ring, a quinoxaline ring, a quinoline ring, apyrimidine ring, a triazine ring, a thiophene ring, a benzothiophenering, a thianthrene ring, a furan ring, a benzofuran ring, a pyrazolering, a pyrazine ring, a pyridazine ring, an indolizine ring, aquinazoline ring, a phenanthroline ring, a silole ring, a benzosilolering, and the like can be given.

Ar′ is preferably a phenyl ring, a naphthyl ring, an anthracene ring, anacenaphthylene ring, a fluorene ring, a phenanthrene ring, afluoranthene ring, a triphenylene ring, a pyrene ring, a chrysene ring,a benzanthracene ring, or a perylene ring.

X′ is a substituent.

In more detail, X′ is a substituted or unsubstituted aromatic grouphaving 6 to 50 nucleus carbon atoms, a substituted or unsubstitutedaromatic heterocyclic group having 5 to 50 nucleus atoms, a substitutedor unsubstituted alkyl group having 1 to 50 carbon atoms, a substitutedor unsubstituted alkoxy group having 1 to 50 carbon atoms, a substitutedor unsubstituted aralkyl group having 1 to 50 carbon atoms, asubstituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms,a substituted or unsubstituted arylthio group having 5 to 50 nucleusatoms, a substituted or unsubstituted carboxyl group having 1 to 50carbon atoms, a substituted or unsubstituted styryl group, a halogenatom, a cyano group, a nitro group, a hydroxyl group, or the like.

As examples of the substituted or unsubstituted aromatic group having 6to 50 nucleus carbon atoms, a phenyl group, 1-naphthyl group, 2-naphthylgroup, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthrylgroup, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group,9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, and 1-pyrenyl group, 2-pyrenyl group, 4-pyrenylgroup, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group,p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group,m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group,o-tolyl group, m-tolyl group, p-tolyl group, p-t-butylphenyl group,p-(2-phenylpropyl)phenyl group, 3-methyl-2-naphthyl group,4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylylgroup, 4″-t-butyl-p-terphenyl-4-yl group, 2-fluorenyl group,9,9-dimethyl-2-fluorenyl group, 3-fluoranthenyl group, and the like canbe given.

The substituted or unsubstituted aromatic group having 6 to 50 nucleuscarbon atoms is preferably a phenyl group, 1-naphthyl group, 2-naphthylgroup, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group,2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, o-tolylgroup, m-tolyl group, p-tolyl group, p-t-butylphenyl group, 2-fluorenylgroup, 9,9-dimethyl-2-fluorenyl group, 3-fluoranthenyl group, or thelike.

As examples of the substituted or unsubstituted aromatic heterocyclicgroup having 5 to 50 nucleus atoms, a 1-pyrrolyl group, 2-pyrrolylgroup, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group, 3-pyridinylgroup, 4-pyridinyl group, 1-indolyl group, 2-indolyl group, 3-indolylgroup, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolylgroup, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolyl group,4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolylgroup, 2-furyl group, 3-furyl group, 2-benzofuranyl group,3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group,6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group,3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranylgroup, 6-isobenzofuranyl group, 7-isobenzofuranyl group, quinolyl group,3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group,7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolylgroup, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolylgroup, 1-phenanthridinyl group, 2-phenanthridinyl group,3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinylgroup, 7-phenanthridinyl group, 8-phenanthridinyl group,9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthrolin-2-yl group, 1,7-phenanthrolin-3-yl group,1,7-phenanthrolin-4-yl group, 1,7-phenanthrolin-5-yl group,1,7-phenanthrolin-6-yl group, 1,7-phenanthrolin-8-yl group,1,7-phenanthrolin-9-yl group, 1,7-phenanthrolin-10-yl group,1,8-phenanthrolin-2-yl group, 1,8-phenanthrolin-3-yl group,1,8-phenanthrolin-4-yl group, 1,8-phenanthrolin-5-yl group,1,8-phenanthrolin-6-yl group, 1,8-phenanthrolin-7-yl group,1,8-phenanthrolin-9-yl group, 1,8-phenanthrolin-10-yl group,1,9-phenanthrolin-2-yl group, 1,9-phenanthrolin-3-yl group,1,9-phenanthrolin-4-yl group, 1,9-phenanthrolin-5-yl group,1,9-phenanthrolin-6-yl group, 1,9-phenanthrolin-7-yl group,1,9-phenanthrolin-8-yl group, 1,9-phenanthrolin-10-yl group,1,10-phenanthrolin-2-yl group, 1,10-phenanthrolin-3-yl group,1,10-phenanthrolin-4-yl group, 1,10-phenanthrolin-5-yl group,2,9-phenanthrolin-1-yl group, 2,9-phenanthrolin-3-yl group,2,9-phenanthrolin-4-yl group, 2,9-phenanthrolin-5-yl group,2,9-phenanthrolin-6-yl group, 2,9-phenanthrolin-7-yl group,2,9-phenanthrolin-8-yl group, 2,9-phenanthrolin-10-yl group,2,8-phenanthrolin-1-yl group, 2,8-phenanthrolin-3-yl group,2,8-phenanthrolin-4-yl group, 2,8-phenanthrolin-5-yl group,2,8-phenanthrolin-6-yl group, 2,8-phenanthrolin-7-yl group,2,8-phenanthrolin-9-yl group, 2,8-phenanthrolin-10-yl group,2,7-phenanthrolin-1-yl group, 2,7-phenanthrolin-3-yl group,2,7-phenanthrolin-4-yl group, 2,7-phenanthrolin-5-yl group,2,7-phenanthrolin-6-yl group, 2,7-phenanthrolin-8-yl group,2,7-phenanthrolin-9-yl group, 2,7-phenanthrolin-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiadinyl group,2-phenothiadinyl group, 3-phenothiadinyl group, 4-phenothiadinyl group,10-phenothiadinyl group, 1-phenoxadinyl group, 2-phenoxadinyl group,3-phenoxadinyl group, 4-phenoxadinyl group, 10-phenoxadinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrol-1-yl group, 2-methylpyrrol-3-yl group,2-methylpyrrol-4-yl group, 2-methylpyrrol-5-yl group,3-methylpyrrol-1-yl group, 3-methylpyrrol-2-yl group,3-methylpyrrol-4-yl group, 3-methylpyrrol-5-yl group,2-t-butyl-pyrrol-4-yl group, 3-(2-phenylpropyl) pyrrol-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group, and the like can be given.

As examples of the substituted or unsubstituted alkyl group having 1 to50 carbon atoms, a methyl group, ethyl group, propyl group, isopropylgroup, n-butyl group, s-butyl group, isobutyl group, t-butyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group,hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group,2-hydroxyisobutyl group, 1,2-dihydroxyethyl group, 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group, 1,2,3-trinitropropyl group,cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexylgroup, 4-methylcyclohexyl group, 1-adamantyl group, 2-adamantyl group,1-norbornyl group, 2-norbornyl group, and the like can be given.

The substituted or unsubstituted alkoxy group having 1 to 50 carbonatoms is a group shown by —OY. As examples of Y, a methyl group, ethylgroup, propyl group, isopropyl group, n-butyl group, s-butyl group,isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptylgroup, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group,2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group, 1,2,3-trinitropropyl group, and thelike can be given.

Examples of the substituted or unsubstituted aralkyl groups having 1 to50 carbon atoms include benzyl, 1-phenylethyl, 2-phenylethyl,1-phenylisopropyl, 2-phenylisopropyl, phenyl-t-butyl, α-naphthylmethyl,1-α-naphthylethyl, 2-α-naphthylethyl, 1-α-naphthylisopropyl,2-α-naphthylisopropyl, β-naphthylmethyl, 1-β-naphthylethyl,2-β-naphthylethyl, 1-β-naphthylisopropyl, 2-β-naphthylisopropyl,1-pyrrolylmethyl, 2-(1-pyrrolyl)ethyl, p-methylbenzyl, m-methylbenzyl,o-methylbenzyl, p-chlorobenzyl, m-chlorobenzyl, o-chlorobenzyl,p-bromobenzyl, m-bromobenzyl, o-bromobenzyl, p-iodobenzyl, m-iodobenzyl,o-iodobenzyl, p-hydroxybenzyl, m-hydroxybenzyl, o-hydroxybenzyl,p-aminobenzyl, m-aminobenzyl, o-aminobenzyl, p-nitrobenzyl,m-nitrobenzyl, o-nitrobenzyl, p-cyanobenzyl, m-cyanobenzyl,o-cyanobenzyl, 1-hydroxy-2-phenylisopropyl, and1-chloro-2-phenylisopropyl groups.

The substituted or unsubstituted aryloxy group having 5 to 50 nucleusatoms is shown by —OY′. As examples of Y′, a phenyl group, 1-naphthylgroup, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthrylgroup, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group,4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group,2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenylgroup, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-t-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group,2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group,3-pyridinyl group, 4-pyridinyl group, 2-indolyl group, 3-indolyl group,4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group,1-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolylgroup, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furylgroup, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group,5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group,1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranylgroup, 5-isobenzofuranyl group, 6-isobenzofuranyl group,7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolylgroup, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolylgroup, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group,5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group,8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group,6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group,3-carbazolyl group, 4-carbazolyl group, 1-phenanthridinyl group,2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinylgroup, 6-phenanthridinyl group, 7-phenanthridinyl group,8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinylgroup, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group,4-acridinyl group, 9-acridinyl group, 1,7-phenanthrolin-2-yl group,1,7-phenanthrolin-3-yl group, 1,7-phenanthrolin-4-yl group,1,7-phenanthrolin-5-yl group, 1,7-phenanthrolin-6-yl group,1,7-phenanthrolin-8-yl group, 1,7-phenanthrolin-9-yl group,1,7-phenanthrolin-10-yl group, 1,8-phenanthrolin-2-yl group,1,8-phenanthrolin-3-yl group, 1,8-phenanthrolin-4-yl group,1,8-phenanthrolin-5-yl group, 1,8-phenanthrolin-6-yl group,1,8-phenanthrolin-7-yl group, 1,8-phenanthrolin-9-yl group,1,8-phenanthrolin-10-yl group, 1,9-phenanthrolin-2-yl group,1,9-phenanthrolin-3-yl group, 1,9-phenanthrolin-4-yl group,1,9-phenanthrolin-5-yl group, 1,9-phenanthrolin-6-yl group,1,9-phenanthrolin-7-yl group, 1,9-phenanthrolin-8-yl group,1,9-phenanthrolin-10-yl group, 1,10-phenanthrolin-2-yl group,1,10-phenanthrolin-3-yl group, 1,10-phenanthrolin-4-yl group,1,10-phenanthrolin-5-yl group, 2,9-phenanthrolin-1-yl group,2,9-phenanthrolin-3-yl group, 2,9-phenanthrolin-4-yl group,2,9-phenanthrolin-5-yl group, 2,9-phenanthrolin-6-yl group,2,9-phenanthrolin-7-yl group, 2,9-phenanthrolin-8-yl group,2,9-phenanthrolin-10-yl group, 2,8-phenanthrolin-1-yl group,2,8-phenanthrolin-3-yl group, 2,8-phenanthrolin-4-yl group,2,8-phenanthrolin-5-yl group, 2,8-phenanthrolin-6-yl group,2,8-phenanthrolin-7-yl group, 2,8-phenanthrolin-9-yl group,2,8-phenanthrolin-10-yl group, 2,7-phenanthrolin-1-yl group,2,7-phenanthrolin-3-yl group, 2,7-phenanthrolin-4-yl group,2,7-phenanthrolin-5-yl group, 2,7-phenanthrolin-6-yl group,2,7-phenanthrolin-8-yl group, 2,7-phenanthrolin-9-yl group,2,7-phenanthrolin-10-yl group, 1-phenazinyl group, 2-phenazinyl group,1-phenothiadinyl group, 2-phenothiadinyl group, 3-phenothiadinyl group,4-phenothiadinyl group, 1-phenoxadinyl group, 2-phenoxadinyl group,3-phenoxadinyl group, 4-phenoxadinyl group, 2-oxazolyl group, 4-oxazolylgroup, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group,3-furazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrol-1-ylgroup, 2-methylpyrrol-3-yl group, 2-methylpyrrol-4-yl group,2-methylpyrrol-5-yl group, 3-methylpyrrol-1-yl group,3-methylpyrrol-2-yl group, 3-methylpyrrol-4-yl group,3-methylpyrrol-5-yl group, 2-t-butylpyrrol-4-yl group,3-(2-phenylpropyl)pyrrol-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group, 4-t-butyl-3-indolyl group, and the like canbe given.

The substituted or unsubstituted arylthio group having 5 to 50 nucleusatoms is shown by —SY″. As examples of Y″, a phenyl group, 1-naphthylgroup, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthrylgroup, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group,4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group,2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenylgroup, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-t-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group,2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group,3-pyridinyl group, 4-pyridinyl group, 2-indolyl group, 3-indolyl group,4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group,1-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolylgroup, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furylgroup, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group,5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group,1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranylgroup, 5-isobenzofuranyl group, 6-isobenzofuranyl group,7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolylgroup, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolylgroup, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group,5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group,8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group,6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group,3-carbazolyl group, 4-carbazolyl group, 1-phenanthridinyl group,2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinylgroup, 6-phenanthridinyl group, 7-phenanthridinyl group,8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinylgroup, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group,4-acridinyl group, 9-acridinyl group, 1,7-phenanthrolin-2-yl group,1,7-phenanthrolin-3-yl group, 1,7-phenanthrolin-4-yl group,1,7-phenanthrolin-5-yl group, 1,7-phenanthrolin-6-yl group,1,7-phenanthrolin-8-yl group, 1,7-phenanthrolin-9-yl group,1,7-phenanthrolin-10-yl group, 1,8-phenanthrolin-2-yl group,1,8-phenanthrolin-3-yl group, 1,8-phenanthrolin-4-yl group,1,8-phenanthrolin-5-yl group, 1,8-phenanthrolin-6-yl group,1,8-phenanthrolin-7-yl group, 1,8-phenanthrolin-9-yl group,1,8-phenanthrolin-10-yl group, 1,9-phenanthrolin-2-yl group,1,9-phenanthrolin-3-yl group, 1,9-phenanthrolin-4-yl group,1,9-phenanthrolin-5-yl group, 1,9-phenanthrolin-6-yl group,1,9-phenanthrolin-7-yl group, 1,9-phenanthrolin-8-yl group,1,9-phenanthrolin-10-yl group, 1,10-phenanthrolin-2-yl group,1,10-phenanthrolin-3-yl group, 1,10-phenanthrolin-4-yl group,1,10-phenanthrolin-5-yl group, 2,9-phenanthrolin-1-yl group,2,9-phenanthrolin-3-yl group, 2,9-phenanthrolin-4-yl group,2,9-phenanthrolin-5-yl group, 2,9-phenanthrolin-6-yl group,2,9-phenanthrolin-7-yl group, 2,9-phenanthrolin-8-yl group,2,9-phenanthrolin-10-yl group, 2,8-phenanthrolin-1-yl group,2,8-phenanthrolin-3-yl group, 2,8-phenanthrolin-4-yl group,2,8-phenanthrolin-5-yl group, 2,8-phenanthrolin-6-yl group,2,8-phenanthrolin-7-yl group, 2,8-phenanthrolin-9-yl group,2,8-phenanthrolin-10-yl group, 2,7-phenanthrolin-1-yl group,2,7-phenanthrolin-3-yl group, 2,7-phenanthrolin-4-yl group,2,7-phenanthrolin-5-yl group, 2,7-phenanthrolin-6-yl group,2,7-phenanthrolin-8-yl group, 2,7-phenanthrolin-9-yl group,2,7-phenanthrolin-10-yl group, 1-phenazinyl group, 2-phenazinyl group,1-phenothiadinyl group, 2-phenothiadinyl group, 3-phenothiadinyl group,4-phenothiadinyl group, 1-phenoxadinyl group, 2-phenoxadinyl group,3-phenoxadinyl group, 4-phenoxadinyl group, 2-oxazolyl group, 4-oxazolylgroup, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group,3-furazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrol-1-ylgroup, 2-methylpyrrol-3-yl group, 2-methylpyrrol-4-yl group,2-methylpyrrol-5-yl group, 3-methylpyrrol-1-yl group,3-methylpyrrol-2-yl group, 3-methylpyrrol-4-yl group,3-methylpyrrol-5-yl group, 2-t-butyl-pyrrol-4-yl group,3-(2-phenylpropyl)pyrrol-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group, 4-t-butyl-3-indolyl group, and the like canbe given.

The substituted or unsubstituted carboxyl group having 1 to 50 carbonatoms is shown by —COOZ′. As examples of Z′, a methyl group, ethylgroup, propyl group, isopropyl group, n-butyl group, s-butyl group,isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptylgroup, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group,2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydroxyethyl group,1,3-dihydroxyisopropyl group, 2, 3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group, 1,2,3-trinitropropyl group, and thelike can be given.

As examples of the substituted or unsubstituted styryl group,2-phenyl-1-vinyl group, 2,2-diphenyl-1-vinyl group,1,2,2-triphenyl-1-vinyl group, and the like can be given.

As examples of the halogen group, fluorine, chlorine, bromine, iodine,and the like can be given.

m is an integer of 1 to 5, and n is an integer of 0 to 6.

m is preferably 1 or 2, and n is preferably 0 to 4.

When m≥2, the Ar's in the parenthesis may be the same or different.

When n≥2, the X's in the parenthesis may be the same or different.

As the material used in the emitting layer, it is further preferable touse an anthracene derivative represented by the following formula (II).A1-L-A2  (II)wherein A1 and A2 are independently a substituted or unsubstitutedmonophenylanthryl group or substituted or unsubstituted diphenylanthrylgroup, and may be the same or different; and L is a single bond or adivalent linking group.

In addition to the anthracene derivative described above, an anthracenederivative represented by the formula (III) can be given.A3-An-A4  (III)wherein An is a substituted or unsubstituted divalent anthraceneresidue; and A3 and A4 are independently a substituted or unsubstitutedmonovalent condensed aromatic ring group or a substituted orunsubstituted non-condensed ring aryl group having 12 or more carbonatoms and may be the same or different.

As the anthracene derivative represented by the formula (II), ananthracene derivative represented by the following formula (II-a) canpreferably be given.

wherein R⁹¹ to R¹⁰⁰ are independently a hydrogen atom, an alkyl group, acycloalkyl group, a substituted or unsubstituted aryl group which may besubstituted, an alkoxy group, an aryloxy group, an alkylamino group, anarylamino group or a heterocyclic group which may be substituted; a andb are independently an integer of 1 to 5; when they are 2 or more, R⁹¹sor R⁹²s may be the same or different, or R⁹¹s or R⁹²s may be bondedtogether to form a ring; R⁹³ and R⁹⁴, R⁹⁵ and R⁹⁶, R⁹⁷ and R⁹⁸, or R⁹⁹and R¹⁰⁰ may be bonded together to form a ring; and L¹⁰ is a singlebond, —O—, —S—, —N(R)— (R is an alkyl group or a substituted orunsubstituted aryl group), or an arylene group.

An anthracene derivative represented by the following formula (II-b) canalso preferably be given.

wherein R¹⁰¹ to R¹¹⁰ are independently a hydrogen atom, an alkyl group,a cycloalkyl group, a substituted or unsubstituted aryl group, an alkoxygroup, an aryloxy group, an alkylamino group, an arylamino group or asubstituted or unsubstituted heterocyclic group; c, d, e and f areindependently an integer of 1 to 5; when they are 2 or more, R¹⁰¹s,R¹⁰²s, R¹⁰⁶ s or R¹⁰⁷s may be the same or different, R¹⁰¹s, R¹⁰²s, R¹⁰⁶sor R¹⁰⁷s may be bonded together to form a ring, or R¹⁰³ and R¹⁰⁴, orR¹⁰⁸ and R¹⁰⁹ may be bonded together to form a ring; and L¹¹ is a singlebond, —O—, —S—, —N(R)— (R is an alkyl group or an aryl group which maybe substituted), or an arylene group.

As for R⁹¹ to R¹¹⁰ shown in the above formulae (II-a) and (II-b), as thealkyl group, an alkyl group having 1 to 6 carbon atoms, as the cyclogroup, a cyclo alkyl group having 3 to 6 carbon atoms, as the arylgroup, an aryl group having 5 to 18 carbon atoms, as the alkoxy group,an alkoxy group having 1 to 6 carbon atoms, as the aryoxy group, anaryloxy group having 5 to 18 carbon atoms, as the arylamino group, anamino group substituted with an aryl group having 5 to 16 carbon atoms,as the heterocyclic group, triazole, oxadiazole, quinoxaline, furanyl,or thienyl or the like can preferably be given.

It is preferred that the alkyl group represented by R in —N(R)— in L¹⁰and L¹¹ have 1 to 6 carbon atoms and that the ary group represented by Rin —N(R)— in L¹⁰ and L¹¹ have 5 to 18 carbon atoms.

As the host material for use in the emitting layer with a dopant whichis described later, the compounds represented by the following formulas(i) to (ix) are preferred. Asymmetrical anthracene represented by thefollowing formula (i)

wherein Ar is a substituted or unsubstituted condensed aromatic grouphaving 10 to 50 nucleus carbon atoms, Ar′ is a substituted orunsubstituted aromatic group having 6 to 50 nucleus carbon atoms, X¹ toX³ are independently a substituted or unsubstituted aromatic grouphaving 6 to 50 nucleus carbon atoms, a substituted or unsubstitutedaromatic heterocyclic group having 5 to 50 nucleus atoms, a substitutedor unsubstituted alkyl group having 1 to 50 carbon atoms, a substitutedor unsubstituted alkoxy group having 1 to 50 carbon atoms, a substitutedor unsubstituted aralkyl group having 6 to 50 carbon atoms, asubstituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms,a substituted or unsubstituted arythio group having 5 to 50 nucleusatoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to50 carbon atoms, a carboxyl group, a halogen atom, a cyano group, anitro group or a hydroxyl group; a, b and c are independently an integerof 0 to 4; and n is an integer of 1 to 3, provided that, when n is twoor more, the groups in [ ] may be the same or different.Asymmetrical monoanthracene derivatives represented by the followingformula (ii)

wherein Ar¹ and Ar² are independently a substituted or unsubstitutedaromatic ring group having 6 to 50 nucleus carbon atoms; and m and n areindependently an integer of 1 to 4, provided that in the case wherem=n=1 and Ar¹ and Ar² are symmetrically bonded to the benzene rings; Ar¹and Ar² are not the same, and in the case where m or n is an integer of2 to 4, m is different from n.

R¹ to R¹⁰ are independently a hydrogen atom, a substituted orunsubstituted aromatic ring group having 6 to 50 nucleus carbon atoms, asubstituted or unsubstituted aromatic hetrocyclic group having 5 to 50nucleus atoms, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, asubstituted or unsubstituted aralkyl group having 6 to 50 carbon atoms,a substituted or unsubstituted aryloxy group having 5 to 50 nucleusatoms, a substituted or unsubstituted arylthio group having 5 to 50nucleus atoms, a substituted or unsubstituted alkoxycarbonyl grouphaving 1 to 50 carbon atoms, a substituted or unsubstituted silyl group,a carboxyl group, a halogen atom, a cyano group, a nitro group or ahydroxy group.

Asymmetrical pyrene derivatives represented by the following formula(iii)

wherein Ar and Ar′ are independently a substituted or unsubstitutedaromatic group having 6 to 50 nucleus carbon atoms; Land L′ areindependently a substituted or unsubstituted phenylene group, asubstituted or unsubstituted naphthalenylene group, a substituted orunsubstituted fluolenylene group, or a substituted or unsubstituteddibenzosilolylene group;

m is an integer of 0 to 2, n is an integer of 1 to 4, s is an integer of0 to 2, and t is an integer of 0 to 4;

L and Ar bonds at any one position of 1 to 5 of the pyrene; and L′ orAr′ bonds at any one position of 6 to 10 of the pyrene; provided thatwhen n+t is an even number, Ar, Ar′, L and L′ satisfy the following (1)or (2):

(1) Ar≠Ar′ and/or L≠L′ where ≠ means these are groups having differentstructures from each other.

(2) when Ar=Ar′ and L=L′,

(2-1) m≠s and/or n≠t, or

(2-2) when m=s and n=t,

(2-2-1) when L, L′ or pyrene bonds at different positions of Ar and Ar′,or (2-2-2) L, L′ or pyrene bonds at the same position of Ar and Ar′, thesubstitution positions of L and L′ or Ar and Ar′ in the pyrene are notnecessarily 1 and 6 positions or 2 and 7 positions.

Asymmetrical anthracene represented by the following formula (iv)

wherein A¹ and A² are independently a substituted or unsubstitutedcondensed aromatic ring group having 10 to 20 nucleus carbon atoms;

Ar¹ and Ar² are independently a hydrogen atom or a substituted orunsubstituted aromatic ring group with 6 to 50 nucleus carbon atoms; and

R¹ to R¹⁰ are independently a hydrogen atom or a substituted orunsubstituted aromatic ring group having 6 to 50 nucleus carbon atoms, asubstituted or unsubstituted aromatic hetrocyclic group having 5 to 50nucleus atoms, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, asubstituted or unsubstituted aralkyl group having 6 to 50 carbon atoms,a substituted or unsubstituted aryloxy group having 5 to 50 nucleusatoms, a substituted or unsubstituted arylthio group having 5 to 50nucleus atoms, a substituted or unsubstituted alkoxycarbonyl grouphaving 1 to 50 carbon atoms, a substituted or unsubstituted silyl group,a carboxyl group, a halogen atom, a cyano group, a nitro group or ahydroxy group;

Each of Ar¹, Ar², R⁹ and R¹⁰ may be plural, and adjacent groups thereofmay form a saturated or unsaturated ring structure.

However, in the formula, groups do not symmetrically bond to 9 and 10positions of the central anthracene with respect to X-Y axis.

A small amount of a phosphor compound may be added to the emitting layeras a dopant to improve emission performance. Dopants known as a dopantmaterial having a long lifetime may be used. It is preferable to use, asthe dopant material of the luminescent material, a material representedby the formula (VI):

In the formula, Ar⁴¹ to Ar⁴³ are a substituted or unsubstituted aromaticgroup having 6 to 50 nucleus carbon atoms or a substituted orunsubstituted styryl group.

As examples of the substituted or unsubstituted aromatic group having 6to 50 nucleus atoms, a phenyl group, 1-naphthyl group, 2-naphthyl group,1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group,2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group,9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, and 1-pyrenyl group, 2-pyrenyl group, 4-pyrenylgroup, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group,p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group,m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group,o-tolyl group, m-tolyl group, p-tolyl group, p-t-butylphenyl group,p-(2-phenylpropyl)phenyl group, 3-methyl-2-naphthyl group,4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylylgroup, 4″-t-butyl-p-terphenyl-4-yl group, 2-fluorenyl group,9,9-dimethyl-2-fluorenyl group, 3-fluoranthenyl group, and the like canbe given.

The substituted or unsubstituted aromatic group having 6 to 50 nucleusatoms is preferably a phenyl group, l-naphthyl group, 2-naphthyl group,9-phenanthryl group, l-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group,2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, o-tolylgroup, m-tolyl group, p-tolyl group, p-t-butylphenyl group, 2-fluorenylgroup, 9,9-dimethyl-2-fluorenyl group, 3-fluoranthenyl group, or thelike.

As examples of the substituted or unsubstituted styryl group,2-phenyl-1-vinyl group, 2,2-diphenyl-1-vinyl group,1,2,2-triphenyl-1-vinyl group, and the like can be given.

p is an integer of 1 to 4.

When p≤2, the Ar⁴² and Ar⁴³ in the parenthesis may be the same ordifferent.

[Hole-Injecting/Transporting Layer]

The hole-injecting/transporting layer is a layer for helping theinjection of holes into the emitting layer to transport the holes to alight-emitting region. The hole mobility thereof is large and theionization energy thereof is usually as small as 5.6 eV or less. Such ahole-injecting/transporting layer is preferably made of a material whichcan transport holes to the emitting layer at a low electric fieldintensity. The hole mobility thereof is preferably at least 10⁻⁴cm²/V·second when an electric field of, e.g., 10⁴ to 10⁶ V/cm isapplied.

In the invention, the hole-injection layer and the hole-transportinglayer may be formed of a plurality of layers. The compounds used in thedevice configuration of the invention, which are represented by theabove formulas (1) and (2), may form a hole-injecting/transporting layeralone or in combination with other materials.

Any materials which have the above preferable properties can be used incombination with the compounds represented by the formulas (1) and (2),which are used in the device configuration of the invention, as thematerial for forming the hole-injecting/transporting layer withoutparticular limitation. The material for forming the hole-injecting layeror the hole-transporting layer can be arbitrarily selected frommaterials which have been widely used as a material transportingcarriers of holes in photoconductive materials and known materials usedin a hole-injecting layer of organic EL devices. Other than the aromaticamine derivative layer and the nitrogen-containing heterocyclicderivative layer, layers constituting the hole-transporting region maybe provided. The material forming such layers may be selectedarbitrarily from the known materials as mentioned above. A compoundrepresented by the following formula can be considered as the aromaticamine derivative.

Ar⁵⁷ to Ar⁶², Ar⁵¹ to Ar⁵³, Ar^(s4) to Ar⁵⁶ are independently asubstituted or unsubstituted aromatic group having 6 to 50 nucleuscarbon atoms or a heteroaromatic group having 5 to 50 nucleus atoms; ato c, and p to r are independently an integer of 0 to 3; and Ar⁵⁷ andAr⁵⁸, Ar⁵⁹ and Ar⁸³, and Ar⁶¹ and Ar⁶² may be bonded to each other toform a saturated or unsaturated ring.

Ar⁷¹ to Ar⁷⁴ are a substituted or unsubstituted aromatic group having 6to 50 nucleus carbon atoms or a heteroaromatic group having 5 to 50nucleus atoms; L¹² is a linking group, a single bond, a substituted orunsubstituted aromatic group having 6 to 50 nucleus carbon atoms, or aheteroaromatic group having 5 to 50 nucleus atoms; x is an integer of 0to 5; and Ar⁷² and Ar⁷³ may be bonded to each other to form a saturatedor unsaturated ring.

Specific examples include triazole derivatives (see U.S. Pat. No.3,112,197 and others), oxadiazole derivatives (see U.S. Pat. No.3,189,447 and others), imidazole derivatives (see JP-B-37-16096 andothers), polyarylalkane derivatives (see U.S. Pat. Nos. 3,615,402,3,820,989 and 3,542,544, JP-B-45-555 and 51-10983, JP-A-51-93224,55-17105, 56-4148, 55-108667, 55-156953 and 56-36656, and others),pyrazoline derivatives and pyrazolone derivatives (see U.S. Pat. Nos.3,180,729 and 4,278,746, JP-A-55-88064, 55-88065, 49-105537, 55-51086,56-80051, 56-88141, 57-45545, 54-112637 and 55-74546, and others),phenylene diamine derivatives (see U.S. Pat. No. 3,615,404,JP-B-51-10105, 46-3712, 47-25336, 54-119925, and others), arylaminederivatives (see U.S. Pat. Nos. 3,567,450, 3,240,597, 3,658,520,4,232,103, 4,175,961 and 4,012,376, JP-B-49-35702 and 39-27577,JP-A-55-144250, 56-119132 and 56-22437, DE1,110,518, and others),amino-substituted chalcone derivatives (see U.S. Pat. No. 3,526,501, andothers), oxazole derivatives (ones disclosed in U.S. Pat. No. 3,257,203,and others), styrylanthracene derivatives (see JP-A-56-46234, andothers), fluorenone derivatives (JP-A-54-110837, and others), hydrazonederivatives (see U.S. Pat. No. 3,717,462, JP-A-54-59143, 55-52063,55-52064, 55-46760, 57-11350, 57-148749 and 2-311591, and others),stilbene derivatives (see JP-A-61-210363, 61-228451, 61-14642, 61-72255,62-47646, 62-36674, 62-10652, 62-30255, 60-93455, 60-94462, 60-174749and 60-175052, and others), silazane derivatives (U.S. Pat. No.4,950,950), polysilanes (JP-A-2-204996), aniline copolymers(JP-A-2-282263), and electroconductive high molecular oligomers (inparticular thiophene oligomers).

The same substances used for the hole-transporting layer can be used asthe material of the hole-injecting layer. The following can also beused: porphyrin compounds (disclosed in JP-A-63-295695 and others),aromatic tertiary amine compounds and styrylamine compounds (see U.S.Pat. No. 4,127,412, JP-A-53-27033, 54-58445, 55-79450, 55-144250,56-119132, 61-295558, 61-98353 and 63-295695, and others). Aromatictertiary amine compounds are particularly preferably used.

The following can also be given as examples:4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (abbreviated by NPDhereinafter), which has in the molecule thereof two condensed aromaticrings, disclosed in U.S. Pat. No. 5,061,569, and4,4′,4″-tris(N-(3-methylphenyl)-N-phenylamino)triphenylamine(abbreviated by MTDATA, hereinafter), wherein three triphenylamine unitsare linked to each other in a star-burst form, disclosed inJP-A-4-308688.

Other than those mentioned above, a nitrogen-containing heterocyclicderivative represented by the following formula, as disclosed inJapanese Patent No. 3571977, can also be used.

wherein R¹²¹ to R¹²⁶ are independently a substituted or unsubstitutedalkyl group, a substituted or unsubstituted aryl group, a substituted orunsubstituted aralkyl group, or a substituted or unsubstitutedheterocyclic group. R¹²¹ to R¹²⁶ may be the same or different. R¹²¹ andR¹²², R¹²³ and R¹²⁴, R¹²⁶ and R¹²⁶, R¹²¹ and R¹²⁶, R¹²² and R¹²³, andR¹²⁴ and R¹²⁵ may form a condensed ring.

Further, a compound represented by the following formula, as describedin the U.S. Patent Publication No. 2004/0113547 can also be used.

wherein R¹³¹ to R¹³⁶ are a substituent, preferably anelectron-attracting group such as a cyano group, a nitro group, asulfonyl group, a carbonyl group, a trifluoromethyl group, or halogen.

The acceptor materials which are represented by these materials can alsobe used as the material for injecting holes. Specific examples thereofare the same as those mentioned above.

Inorganic compounds such as aromatic dimethylidene type compounds,mentioned above as the material for an emitting layer, and p-type Si andp-type SiC can also be used as the material of the hole-injecting layer.

The hole-injecting/transporting layer can be formed from theabove-mentioned compounds by a known method such as vacuum vapordeposition, spin coating, casting or LB technique. The film thickness ofthe hole-injecting/transporting layer is not particularly limited, andis usually from 5 nm to 5 μm. This hole-injecting layer/transportinglayer may be a single layer made of one or more of the above-mentionedmaterials, or may be stacked hole-injecting layers or hole-transportinglayers made of different compounds, insofar as the compound of theinvention is contained in the hole-transporting region.

Further, an organic semiconductor layer may be provided. The organicsemiconductor layer is a layer for helping the injection of holes orelectrons into the emitting layer, and is preferably a layer having anelectric conductivity of 10⁻¹⁰ S/cm or more. As the material of such anorganic semiconductor layer, electroconductive oligomers such asthiophene-containing oligomers or arylamine-containing oligomersdisclosed in JP-A-8-193191, and electroconductive dendrimers such asarylamine-containing dendrimers may be used.

[Electron-Injecting/Transporting Layer]

The electron injecting/transporting layer is a layer which assistsinjection of electrons into the emitting layer, and exhibits a highelectron mobility. An adhesion-improving layer is one of theelectron-injecting layers and is formed of a material which exhibitsexcellent adhesion to the cathode. The material used in theelectron-transporting layer is preferably a metal complex of8-hydroxyquinoline or a derivative thereof.

As specific examples of a metal complex of 8-hydroxyquinoline and itsderivative, metal chelate oxinoid compounds including a chelate of oxine(8-quinolinol or 8-hydroxyquinoline) can be given.

For example, Alq described as the luminescent material can be used forthe electron-injecting layer.

An electron-transporting compound of the following general formula canbe given as the oxadiazole derivative.

wherein Ar⁸¹, Ar⁸², Ar⁸³, Ar⁸⁵, Ar⁸⁶, and Ar⁸⁹ are independentlysubstituted or unsubstituted aryl groups and may be the same ordifferent; and Ar⁸⁴, Ar⁸⁷ and Ar⁸⁸ are a substituted or unsubstitutedarylene group and may be the same or different.

As examples of the aryl group, a phenyl group, a biphenyl group, ananthranyl group, a perylenyl group, and a pyrenyl group can be given. Asexamples of the arylene group, a phenylene group, a naphthylene group, abiphenylene group, an anthranylene group, a perylenylene group, apyrenylene group, and the like can be given. As the substituent, analkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10carbon atoms, a cyano group, and the like can be given. Theelectron-transporting compound is preferably one from which a thin filmcan be formed.

The following compounds can be given as specific examples of theelectron-transporting compound.

The nitrogen-containing heterocyclic derivatives represented by thefollowing formulas (A) and (B) can be used in the electron-injectinglayer.

Nitrogen-containing heterocyclic ring derivatives represented by theformulas (A) and (B) wherein A²¹ to A²³ are independently a nitrogenatom or a carbon atom; Ar²¹ is a substituted or unsubstituted aryl grouphaving 6 to 60 nucleus carbon atoms or a substituted or unsubstitutedheteroaryl group having 3 to 60 nucleus carbon atoms; Ar²² is a hydrogenatom, a substituted or unsubstituted aryl group having 6 to 60 nucleuscarbon atoms, a substituted or unsubstituted heteroaryl group having 3to 60 nucleus carbon atoms, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 20 carbon atoms, or a divalent group of these; provided thatone of Ar²¹ and Ar²² is a substituted or unsubstituted condensed ringgroup having 10 to 60 carbon atoms or a substituted or unsubstitutedmonoheterocondensed ring group having 3 to 60 carbon atoms or a divalentgroup of these;

Ar²³ is a substituted or unsubstituted arylene group having 6 to 60carbon atoms or a substituted or unsubstituted heteroarylene grouphaving 3 to 60 carbon atoms;

L¹¹, L¹², and L¹³ are independently a single bond, a substituted orunsubstituted arylene group having 6 to 60 carbon atoms, a substitutedor unsubstituted heteroarylene group having 3 to 60 carbon atoms, or asubstituted or unsubstituted fluorenylene group.

R⁸¹ is a hydrogen atom, a substituted or unsubstituted aryl group having6 to 60 nucleus carbon atoms, a substituted or unsubstituted heteroarylgroup having 3 to 60 nucleus carbon atoms, a substituted orunsubstituted alkyl group having 1 to carbon atoms, or a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms, and n is aninteger of 0 to 5, provided that, when n is an integer of 2 or more, aplurality of R⁸¹s may be the same or different; adjacent R⁸¹s may bebonded to form a carbocyclic aliphatic ring or a carbocyclic aromaticring;

R⁸² is a hydrogen atom, a substituted or unsubstituted aryl group having6 to 60 nucleus carbon atoms, a substituted or unsubstituted heteroarylgroup having 3 to 60 nucleus carbon atoms, a substituted orunsubstituted alkyl group having 1 to carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms or-L¹¹-Ar²¹—Ar²².

Nitrogen-containing heterocyclic ring derivatives of the followingformula (C)HAr-L¹⁴-Ar²⁴—Ar²⁵wherein HAr is a nitrogen-containing heterocyclic ring having 3 to 40carbon atoms which may have a substituent; L¹⁴ is a single bond, anarylene group having 6 to 60 carbon atoms which may have a substituent,a heteroarylene group having 3 to 60 carbon atoms which may have asubstituent or a fluorenylene group which may have a substituent; Ar²⁴is a divalent aromatic hydrocarbon group having 6 to 60 carbon atomswhich may have a substituent; and Ar²⁵ is an aryl group with 6 to 60carbon atoms which may have a substituent or a heteroaryl group having 3to 60 carbon atoms which may have a substituent.

Silacyclopentadiene derivative represented by the formula (D) whereinX¹¹ and Y¹¹ are individually a saturated or unsaturated hydrocarbongroup having 1 to 6 carbon atoms, an alkoxy group, an alkenyloxy group,an alkynyloxy group, a hydroxyl group, a substituted or unsubstitutedaryl group, or a substituted or unsubstituted heterocyclic ring, or X¹¹and Y¹¹ are bonded to form a saturated or unsaturated ring, and R¹⁵ toR³⁸ are independently a hydrogen atom, a halogen atom, a substituted orunsubstituted aryl group having 1 to 6 carbon atoms, an alkoxy group, anaryloxy group, a perfluoroalkyl group, a perfluoroalkoxy group, an aminogroup, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonylgroup, an aryloxycarbonyl group, an azo group, an alkylcarbonyloxygroup, an arylcarbonyloxy group, an alkoxycarbonyloxy group, anaryloxycarbonyloxy group, a sulfinyl group, a sulfonyl group, a sulfanylgroup, a silyl group, a carbamoyl group, an aryl group, a heterocyclicgroup, an alkenyl group, an alkynyl group, a nitro group, a formylgroup, a nitroso group, a formyloxy group, an isocyano group, a cyanategroup, an isocyanate group, a thiocyanate group, an isothiocyanategroup, or a cyano group, or adjacent groups thereof form a substitutedor unsubstituted condensed ring.

Boran derivative represented by the formula (E) wherein R⁹¹ to R⁹⁸ andZ² are independently a hydrogen atom, a saturated or unsaturatedhydrocarbon group, an aromatic group, a heterocyclic group, asubstituted amino group, a substituted boryl group, an alkoxy group, oran aryloxy group, X¹², Y¹², and Z¹ are independently a saturated orunsaturated hydrocarbon group, an aromatic group, a heterocyclic group,a substituted amino group, an alkoxy group, or an aryloxy group, thesubstituents for Z¹ and Z² may be bonded to form a condensed ring, n isan integer of 1 to 3, provided that the Z's may differ when n is 2 ormore, and a case in which n is 1, X¹², Y¹², and R⁹² are methyl groups,and R⁹⁸ is a hydrogen atom or a substituted boryl group, and a case inwhich n is 3 and Z₁ is a methyl group are excluded.

wherein Q¹ and Q² are independently ligands of the following formula(G), L¹⁵ is a halogen atom, a substituted or unsubstituted alkyl group,a substituted or unsubstituted cycloalkyl group, a substituted orunsubstituted aryl group, a substituted or unsubstituted heterocyclicgroup, —OR′ (R′ is a hydrogen atom, a substituted or unsubstituted alkylgroup, a substituted or unsubstituted cycloalkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted heterocyclicgroup), or —O—Ga-Q³(Q⁴) (Q³ and Q⁴ have the same meanings as Q¹ and Q²).

wherein rings A²⁴ and A²⁵ are independently a 6-membered aryl ringstructure which may have a substituent, and are condensed to each other.

The metal complexes have the strong nature of an n-type semiconductorand large ability of injecting electrons. Further, the energy generatedat the time of forming a complex is small so that a metal is thenstrongly bonded to ligands in the complex formed and the fluorescentquantum efficiency becomes large as the luminescent material.

Specific examples of the substituents for the rings A²⁴ and A²⁵ formingthe ligand of the formula (G) include halogen atoms such as chlorine,bromine, iodine, and fluorine, substituted or unsubstituted alkyl groupssuch as a methyl group, ethyl group, propyl group, butyl group,sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptylgroup, octyl group, stearyl group, and trichloromethyl group, asubstituted or unsubstituted aryl groups such as a phenyl group,naphthyl group, 3-methylphenyl group, 3-methoxyphenyl group,3-fluorophenyl group, 3-trichloromethylphenyl group,3-trifluoromethylphenyl group, and 3-nitrophenyl group, a substituted orunsubstituted alkoxy groups such as a methoxy group, n-butoxy group,tert-butoxy group, trichloromethoxy group, trifluoroethoxy group,pentafluoropropoxy group, 2,2,3,3-tetrafluoropropoxy group,1,1,1,3,3,3-hexafluoro-2-propoxy group, and 6-(perfluoroethyl)hexyloxygroup, a substituted or unsubstituted aryloxy groups such as a phenoxygroup, p-nitrophenoxy group, p-tert-butylphenoxy group, 3-fluorophenoxygroup, pentafluorophenyl group, and 3-trifluoromethylphenoxy group, asubstituted or unsubstituted alkylthio groups such as a methylthiogroup, ethylthio group, tert-butylthio group, hexylthio group, octylthiogroup, and trifluoromethylthio group, a substituted or unsubstitutedarylthio groups such as a phenylthio group, p-nitrophenylthio group,p-tert-butylphenylthio group, 3-fluorophenylthio group,pentafluorophenylthio group, and 3-trifluoromethylphenylthio group, acyano group, a nitro group, an amino group, mono- or di-substitutedamino groups such as a methylamino group, diethylamino group, ethylaminogroup, diethylamino group, dipropylamino group, dibutylamino group, anddiphenylamino group, acylamino groups such as a bis(acetoxymethyl)aminogroup, bis(acetoxyethyl)amino group, bis(acetoxypropyl)amino group, andbis(acetoxybutyl)amino group, a hydroxyl group, a siloxy group, an acylgroup, a substituted or unsubstituted carbamoyl group such as acarbamoyl group, a methylcarbamoyl group, dimethylcarbamoyl group,ethylcarbamoyl group, diethylcarbamoyl group, propylcarbamoyl group,butylcarbamoyl group, and phenylcarbamoyl group, a carboxylic acidgroup, a sulfonic acid group, an imide group, cycloalkyl groups such asa cyclopentane group and a cyclohexyl group, aryl groups such as aphenyl group, naphthyl group, biphenyl group, anthranyl group,phenanthryl group, fluorenyl group, and pyrenyl group, heterocyclicgroups such as a pyridinyl group, pyrazinyl group, pyrimidinyl group,pyridazinyl group, triazinyl group, indolinyl group, quinolinyl group,acridinyl group, pyrrolidinyl group, dioxanyl group, piperidinyl group,morpholidinyl group, piperazinyl group, carbazolyl group, furanyl group,thiophenyl group, oxazolyl group, triathinyl group, oxadiazolyl group,benzooxazolyl group, thiazolyl group, thiadiazolyl group, benzothiazolylgroup, triazolyl group, imidazolyl group, benzimidazolyl group, pranylgroup, and the like. The above substituents may be bonded to form asix-membered aryl ring or heterocyclic ring.

Polymer compounds containing a nitrogen-containing heterocyclic group ornitrogen-containing heterocyclic derivative may also be used.

A preferred embodiment of the invention is a device containing areducing dopant in an interfacial region between itselectron-transferring region or cathode and organic layer. The reducingdopant is defined as a substance which can reduce anelectron-transferring compound. Accordingly, various substances whichhave given reducing properties can be used. For example, at least onesubstance can be preferably used which is selected from the groupconsisting of alkali metals, alkaline earth metals, rare earth metals,alkali metal oxides, alkali metal halides, alkaline earth metal oxides,alkaline earth metal halides, rare earth metal oxides, rare earth metalhalides, alkali metal organic complexes, alkaline earth metal organiccomplexes, and rare earth metal organic complexes.

More specific examples of the preferred reducing dopants include atleast one alkali metal selected from the group consisting of Na (workfunction: 2.36 eV), K (work function: 2.28 eV), Rb (work function: 2.16eV) and Cs (work function: 1.95 eV), and at least one alkaline earthmetal selected from the group consisting of Ca (work function: 2.9 eV),Sr (work function: 2.0 to 2.5 eV), and Ba (work function: 2.52 eV).Metals having a work function of 2.9 eV or less are particularlypreferred. Among these, a more preferable reducing dopant is at leastone alkali metal selected from the group consisting of K, Rb and Cs.Even more preferable is Rb or Cs. Most preferable is Cs. These alkalimetals are particularly high in reducing ability. Thus, the addition ofa relatively small amount thereof to an electron-injecting zone improvesthe luminance of the organic EL device and make the lifetime thereoflong. As a reducing agent having work function of 2.9 eV or less,combinations of two ore more alkali metals are preferable, particularlycombinations including Cs, such as Cs and Na, Cs and K, Cs and Rb, orCs, Na and K are preferable. The combination containing Cs makes itpossible to exhibit the reducing ability efficiently. The luminance ofthe organic EL device can be improved and the lifetime thereof can bemade long by the addition thereof to its electron-injecting zone.

In the invention, an electron-injecting layer of an insulator and asemiconductor may be further formed between a cathode and an organiclayer. By forming the electron-injecting layer, a current leakage can beefficiently prevented and electron-injecting properties can be improved.As the insulator, at least one metal compound selected from the groupconsisting of alkali metal calcogenides, alkaline earth metalcalcogenides, halides of alkali metals and halides of alkaline earthmetals can be preferably used. When the electron-injecting layer isformed of the alkali metal calcogenide or the like, the injection ofelectrons can be preferably further improved.

Specifically preferable alkali metal calcogenides include Li₂O, LiO,Na₂S, Na₂Se and NaO and preferable alkaline earth metal calcogenidesinclude CaO, BaO, SrO, BeO, BaS and CaSe. Preferable halides of alkalimetals include LiF, NaF, KF, LiCl, KCl and NaCl. Preferable halides ofalkaline earth metals include fluorides such as CaF, BaF₂, SrF₂, MgF₂and BeF₂ and halides other than fluorides.

Semiconductors forming an electron-transporting layer include one orcombinations of two ore more of oxides, nitrides, and oxidized nitridescontaining at least one element of Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na,Cd, Mg, Si, Ta, Sb and Zn. An inorganic compound forming anelectron-transporting layer is preferably a microcrystalline oramorphous insulating thin film. When the electron-transporting layer isformed of the insulating thin films, more uniformed thin film is formedwhereby pixel defects such as a dark spot are decreased. Examples ofsuch an inorganic compound include the above-mentioned alkali metalcalcogenides, alkaline earth metal calcogenides, halides of alkalimetals, and halides of alkaline earth metals.

[Cathode]

For the cathode, the following may be used: an electrode substance madeof a metal, an alloy or an electroconductive compound, or a mixturethereof which has a small work function (4 eV or less). Specificexamples of the electrode substance include sodium, sodium-potassiumalloy, magnesium, lithium, magnesium/silver alloy, aluminum/aluminumoxide, aluminum/lithium alloy, indium, and rare earth metals.

This cathode can be formed by making the electrode substances into athin film by deposition, sputtering or some other method.

In the case where emission from the emitting layer is outcoupled throughthe cathode, it is preferred to make the transmittance of the cathode tothe emission larger than 10.

The sheet resistance of the cathode is preferably several hundreds Ω/□or less, and the film thickness thereof is usually from 5 nm to 1 μm,preferably from 5 to 200 nm.

To make the cathode semi-transparent and semi-reflective, it willsuffice that the film thickness of the above materials is adjusted.

[Insulative Layer]

In the organic EL device, pixel defects based on leakage or a shortcircuit are easily generated since an electric field is applied to thesuper thin film. In order to prevent this, it is preferred to insert aninsulative thin layer between the pair of electrodes.

Examples of the material used in the insulative layer include aluminumoxide, lithium fluoride, lithium oxide, cesium fluoride, cesium oxide,magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride,cesium fluoride, cesium carbonate, aluminum nitride, titanium oxide,silicon oxide, germanium oxide, silicon nitride, boron nitride,molybdenum oxide, ruthenium oxide, and vanadium oxide.

A mixture or laminate thereof may be used.

[Example of Fabricating Organic EL Device]

The organic EL device can be fabricated by forming an anode, an emittinglayer and, optionally forming a hole-injecting layer and anelectron-injecting layer if necessary, and further forming a cathode byuse of the materials and methods exemplified above. The organic ELdevice can be fabricated in the order reverse to the above, i.e., theorder from a cathode to an anode.

An example of the fabrication of the organic EL device will be describedbelow which has a structure wherein the following are successivelyformed on a transparent substrate: anode/hole-injectinglayer/hole-transporting layer/emitting layer/electron-transportinglayer/cathode.

First, a thin film made of an anode material is formed into a thicknessof 1 μm or less, preferably 10 to 200 nm on an appropriate transparentsubstrate by deposition, sputtering or some other method, therebyforming an anode.

Next, a hole-injecting layer formed of the compound of the above formula(2) is provided. As described above, the hole-injecting layer can beformed by vacuum vapor deposition, spin coating, casting, LB technique,or some other method. Vacuum vapor deposition is preferred since ahomogenous film is easily obtained and pinholes are not easilygenerated. In the case where the hole-injecting layer is formed byvacuum vapor deposition, conditions for the deposition vary dependingupon a compound used (a material for the hole-injecting layer), adesired crystal structure or recombining structure of the hole-injectinglayer, and others. In general, the conditions are preferably selectedfrom the following: deposition source temperature of 50 to 450° C.,vacuum degree of 10⁻⁷ to 10⁻³ torr, deposition rate of 0.01 to 50nm/second, substrate temperature of −50 to 300° C., and film thicknessof 5 nm to 5 μm.

On the hole-injecting layer, a hole-transporting layer formed of thecompound represented by the above formula (1) is provided. Theconditions and methods for forming the hole-transporting layer are thesame as those for forming the hole-injecting layer.

Next, an emitting layer is formed on the thus-formed hole-transportinglayer. The emitting layer can also be formed by making a desired organicluminescent material into a thin film by vacuum vapor deposition,sputtering, spin coating, casting or some other method. Vacuum vapordeposition is preferred since a homogenous film is easily obtained andpinholes are not easily generated. In the case where the emitting layeris formed by vacuum vapor deposition, conditions for the deposition,which vary depending on a compound used, can be generally selected fromconditions similar to those for the hole-transporting layer.

Next, an electron-transporting layer is formed on this emitting layer.Like the hole-transporting layer and the emitting layer, the layer ispreferably formed by vacuum vapor deposition because a homogenous filmis required. Conditions for the deposition can be selected fromconditions similar to those for the hole-transporting layer and theemitting layer.

Lastly, a cathode is stacked thereon to obtain an organic EL device.

The cathode is made of a metal, and vacuum vapor deposition orsputtering may be used. However, vacuum vapor deposition is preferred inorder to protect underlying organic layers from being damaged when thecathode film is formed.

For the organic EL device fabrication that has been described above, itis preferred that the formation from the anode to the cathode iscontinuously carried out, using only one vacuuming operation.

The method for forming each of the layers in the organic EL device ofthe invention is not particularly limited. A known forming method suchas vacuum vapor deposition or spin coating can be used. An organic thinfilm layer including the compound represented by the above formula (1)used in the organic EL device of the invention may be formed using aknown method such as vacuum vapor deposition, molecular beam epitaxy(MBE), or a coating method using a solution in which the material isdissolved in a solvent, such as dipping, spin coating, casting, barcoating, or roll coating.

The film thickness of each of the organic layers in the organic ELdevice of the invention is not particularly limited. In general, defectssuch as pinholes are easily generated when the film thickness is toosmall. Conversely, when the film thickness is too large, a high appliedvoltage becomes necessary, leading to low efficiency. Usually, the filmthickness is preferably in the range of several nanometers to onemicrometer.

If a DC voltage is applied to the organic EL device, emission can beobserved when the polarities of the anode and the cathode are positiveand negative, respectively, and a DC voltage of 5 to 40 V is applied.When a voltage with an opposite polarity is applied, no electric currentflows and hence, emission does not occur. If an AC voltage is applied,uniform emission can be observed only when the anode and the cathodehave a positive polarity and a negative polarity, respectively. Thewaveform of the AC applied may be arbitrary.

EXAMPLES

The invention will be described in detail referring to the followingexamples, which should not be construed as limiting the scope of theinvention.

Example 1

A glass substrate of 25 mm by 75 mm by 1.1 mm thick with an ITOtransparent electrode (anode) (GEOMATEC CO., LTD.) was subjected toultrasonic cleaning with isopropyl alcohol for 5 minutes, and cleanedwith ultraviolet rays and ozone for 30 minutes. The resultant substratewith transparent electrode lines was mounted on a substrate holder in avacuum deposition device. First, a film of the compound B-1 representedby the following formula was formed as the hole-injecting layer in athickness of 60 nm so as to cover the transparent electrode on thesurface where the transparent electrode lines were formed. Subsequently,a film of the compound A-10 represented by the following formula wasformed on the B-1 film in a thickness of nm as the hole-transportinglayer.

On the A-10 film, a film of an anthracene derivative AN-1 and astyrylamine derivative D-1 represented by the following formulas (filmthickness ratio: AN-1:D-1=40:2) was formed in a thickness of 40 nm toform a blue-emitting layer. On the blue emitting layer, a film of an Alqrepresented by the following formula was formed as theelectron-transporting layer in a thickness of 20 nm by deposition.Thereafter, an LiF film was formed in a thickness of 1 nm as theelectron-injecting layer and metal Al was deposited in a thickness of150 nm as a metal cathode, thereby fabricating an organic EL device.

Example 2

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-2 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 3

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-6 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 4

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-9 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 5

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-11 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 6

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-15 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 7

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-25 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 8

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-26 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 9

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-28 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 10

An organic EL device was fabricated in the same manner as in Example 1,except that the compound A-29 represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Example 11

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-5 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Example 12

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-7 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Example 13

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-8 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Example 14

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-12 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Example 15

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-25 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Example 16

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-27 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Example 17

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-33 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Example 18

An organic EL device was fabricated in the same manner as in Example 1,except that the compound B-39 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Comparative Example 1

An organic EL device was fabricated in the same manner as in Example 1,except that the compound (E-1) represented by the following formula wasused instead of the compound A-10 as the hole-transporting layer.

Comparative Example 2

An organic EL device was fabricated in the same manner as in Example 1,except that the compound E-2 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer, and thecompound B-1 was used instead of the compound A-10 as thehole-transporting layer.

Comparative Example 3

An organic EL device was fabricated in the same manner as in Example 1,except that the compound E-2 represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Comparative Example 4

An organic EL device was fabricated in the same manner as in Example 1,except that the compound (E-3) represented by the following formula wasused instead of the compound B-1 as the hole-injecting layer.

Comparative Example 5

An organic EL device was fabricated in the same manner as in Example 1,except that the thickness of the hole-injecting layer formed of thecompound B-1 was changed to 80 nm, and the hole-transporting layer wasnot formed.

Comparative Example 6

An organic EL device was fabricated in the same manner as in ComparativeExample 5, except that the compound A-10 was used instead of thecompound B-1 as the hole-injecting layer.

Comparative Example 7

An organic EL device was fabricated in the same manner as in ComparativeExample 5, except that the compound B-39 was used instead of thecompound B-1 as the hole-injecting layer.

The performance of each device fabricated in Examples 1 to 18 andComparative Examples 1 to 7 is shown in Table 1.

TABLE 1 Hole- Hole- trans- Luminous Color of injecting porting Voltageefficiency emitted Life layer layer (V) (cd/A) light time Example 1 B-1A-10 6.9 8.2 blue 8000 Example 2 B-1 A-2 7.1 8.3 blue 7000 Example 3 B-1A-6 7 8.3 blue 7000 Example 4 B-1 A-9 6.9 8.3 blue 8000 Example 5 B-1A-11 6.9 8.2 blue 8000 Example 6 B-1 A-15 6.9 8.3 blue 8000 Example 7B-1 A-25 7.1 8.3 blue 8000 Example 8 B-1 A-26 7 8.2 blue 8000 Example 9B-1 A-28 7 8.2 blue 8000 Example 10 B-1 A-29 7 8.2 blue 8000 Example 11B-5 A-10 6.9 8.3 blue 8000 Example 12 B-7 A-10 6.9 8.3 blue 8000 Example13 B-8 A-10 6.9 8.3 blue 8000 Example 14 B-12 A-10 6.9 8.3 blue 8000Example 15 B-25 A-10 6.9 8.3 blue 8000 Example 16 B-27 A-10 6.9 8.3 blue8000 Example 17 B-33 A-10 6.9 8.3 blue 8000 Example 18 B-39 A-10 6.9 8.2blue 8000 Comparative B-1 E-1 7.3 6.7 blue 500 Example 1 Comparative E-2B-1 6.8 6.5 blue 8000 Example 2 Comparative E-2 A-10 8.9 8.2 blue 500Example 3 Comparative E-3 A-10 8.5 8.3 blue 500 Example 4 ComparativeB-1 — 6.8 6.5 blue 7000 Example 5 Comparative A-10 — 10.5 8.3 blue 500Example 6 Comparative B-39 — 6.5 4.1 blue 600 Example 7

Example 19

A glass substrate of 25 mm by 75 mm by 1.1 mm thick with an ITOtransparent electrode (anode) (GEOMATEC CO., LTD.) was subjected toultrasonic cleaning with isopropyl alcohol for 5 minutes, and cleanedwith ultraviolet rays and ozone for 30 minutes. The resultant substratewith transparent electrode lines was mounted on a substrate holder in avapor vacuum deposition device. First, a film of an acceptor compoundC-1 represented by the following formula was formed in a thickness of 10nm as the hole-injecting layer so as to cover the transparent electrodeon the surface where the transparent electrode lines were formed.

Subsequently, on the C-1 film, a film of the compound B-1 was formed ina thickness of 50 nm as the hole-transporting layer (1).

Then, on the B-1 film, a film of the compound A-10 was formed in athickness of 20 nm as the hole-transporting layer (2).

Further, on the A-10 film, a film of AN-1 and D-1 (film thickness ratio:AN-1:D-1=40:2) was formed in a thickness of nm to form a blue-emittinglayer.

On the blue-emitting layer, a 20-thick Alq film was formed bydeposition. Thereafter, an LiF film was formed in a thickness of 1 nm asan electron-injecting layer and metal A1 was deposited in a thickness of150 nm as a metal cathode thereon, thereby fabricating an organic ELdevice.

Example 20

An organic EL device was fabricated in the same manner as in Example 19,except that the compound C-2 represented by the following formula wasused instead of the compound C-1 as the hole-injecting layer.

Example 21

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-2 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 22

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-6 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 23

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-9 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 24

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-11 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 25

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-15 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 26

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-25 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 27

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-26 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 28

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-28 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 29

An organic EL device was fabricated in the same manner as in Example 19,except that the compound A-29 was used instead of the compound A-10 asthe hole-transporting layer (2).

Example 30

An organic EL device was fabricated in the same manner as in Example 19,except that the compound (B-2) was used instead of the compound B-1 asthe hole-transporting layer (1).

Example 31

An organic EL device was fabricated in the same manner as in Example 19,except that the compound B-5 was used instead of the compound B-1 as thehole-transporting layer (1).

Example 32

An organic EL device was fabricated in the same manner as in Example 19,except that the compound B-7 was used instead of the compound B-1 as thehole-transporting layer (1).

Example 33

An organic EL device was fabricated in the same manner as in Example 19,except that the compound B-8 was used instead of the compound B-1 as thehole-transporting layer (1).

Example 34

An organic EL device was fabricated in the same manner as in Example 19,except that the compound B-12 was used instead of the compound B-1 asthe hole-transporting layer (1).

Example 35

An organic EL device was fabricated in the same manner as in Example 19,except that the compound B-25 was used instead of the compound B-1 asthe hole-transporting layer (1).

Example 36

An organic EL device was fabricated in the same manner as in Example 19,except that the compound B-33 was used instead of the compound B-1 asthe hole-transporting layer (1).

Example 37

An organic EL device was fabricated in the same manner as in Example 19,except that the compound B-39 was used instead of the compound B-1 asthe hole-transporting layer (1).

Comparative Example 8

An organic EL device was fabricated in the same manner as in Example 19,except that the compound E-2 was used instead of the compound B-1 as thehole-transporting layer (1).

Comparative Example 9

An organic EL device was fabricated in the same manner as in Example 19,except that the compound E-3 was used instead of the compound B-1 as thehole-transporting layer (1).

Comparative Example 10

An organic EL device was fabricated in the same manner as in Example 19,except that the compound E-3 was used instead of the compound B-1 as thehole-transporting layer (1), and the compound B-1 was used instead ofthe compound A-10 as the hole-transporting layer (2).

Comparative Example 11

A glass substrate of 25 mm by 75 mm by 1.1 mm thick with an ITOtransparent electrode (anode) (GEOMATEC CO., LTD.) was subjected toultrasonic cleaning with isopropyl alcohol for 5 minutes, and cleanedwith ultraviolet rays and ozone for 30 minutes. The resultant substratewith transparent electrode lines was mounted on a substrate holder in avacuum vapor deposition device. First, a film of the acceptor compound(C-1) was formed in a thickness of 60 nm as the hole-injecting layer soas to cover the transparent electrode on the surface where thetransparent electrode lines were formed. Subsequently, on the C-1 film,a film of the compound A-10 was formed in a thickness of 20 nm as thehole-transporting layer.

Further, on the A-10 film, a film of AN-1 and D-1 (a film thicknessratio: AN-1:D-1=40:2) was formed in a thickness of nm to form ablue-emitting layer.

On the blue emitting layer, a 20 nm-thick film of Alq was formed bydeposition as the electron-transporting layer. Thereafter, an LiF filmwas formed in a thickness of 1 nm as an electron-injecting layer andmetal A1 was deposited thereon in a thickness of 150 nm as a metalcathode, thereby fabricating an organic EL device.

Comparative Example 12

An organic EL device was fabricated in the same manner as in ComparativeExample 11, except that the compound B-1 was used instead of thecompound A-10 as the hole-transporting layer.

Comparative Example 13

An organic EL device was fabricated in the same manner as in ComparativeExample 11, except that the compound B-39 was used instead of thecompound A-10 as the hole-transporting layer.

The performance of each device fabricated in Examples 19 to 37 andComparative Examples 8 to 13 is shown in Table 2.

TABLE 2 Hole- Hole- Hole- trans- trans- Luminous Color of injectingporting porting Voltage efficiency emitted Life layer layer 1 layer 2(V) (cd/A) light time Example 19 C-1 B-1 A-10 6.4 8.2 blue 8000 Example20 C-2 B-1 A-10 6.4 8.2 blue 8000 Example 21 C-1 B-1 A-2 6.6 8.3 blue7000 Example 22 C-1 B-1 A-6 6.5 8.3 blue 7000 Example 23 C-1 B-1 A-9 6.48.3 blue 8000 Example 24 C-1 B-1 A-11 6.4 8.2 blue 8000 Example 25 C-1B-1 A-15 6.4 8.3 blue 8000 Example 26 C-1 B-1 A-25 6.6 8.3 blue 8000Example 27 C-1 B-1 A-26 6.5 8.2 blue 8000 Example 28 C-1 B-1 A-28 6.58.2 blue 8000 Example 29 C-1 B-1 A-29 6.5 8.2 blue 8000 Example 30 C-1B-2 A-10 6.4 8.3 blue 8000 Example 31 C-1 B-5 A-10 6.4 8.3 blue 8000Example 32 C-1 B-7 A-10 6.4 8.3 blue 8000 Example 33 C-1 B-8 A-10 6.48.3 blue 8000 Example 34 C-1 B-12 A-10 6.4 8.3 blue 8000 Example 35 C-1B-25 A-10 6.4 8.3 blue 8000 Example 36 C-1 B-33 A-10 6.4 8.3 blue 8000Example 37 C-1 B-39 A-10 6.4 8.3 blue 8000 Comp. C-1 E-2 A-10 8.9 8.2blue 500 Example 8 Comp. C-1 E-3 A-10 8.9 8.2 blue 500 Example 9 Comp.C-1 E-3 B-1 6.9 6 blue 5000 Example 10 Comp. C-1 A-10 10.5 7.5 blue 500Example 11 Comp. C-1 B-1  6.6 6.5 blue 7000 Example 12 Comp. C-1 B-396.3 3.9 blue 600 Example 13

The physical properties of the representative materials used in Examplesand Comparative Examples are shown in Table 3.

TABLE 3 Ionization Electron Energy Hole Potential affinity gap mobilityCompound (eV) (eV) (eV) (cm²/Vs) E-1 5.6 2.42 3.18 1 × 10⁻⁴ E-2 5.2 1.93.3 3 × 10⁻⁴ B-1 5.5 2.41 3.09 9 × 10⁻⁴ A-10 5.52 2.34 3.18 1 × 10⁻⁴AN-1 5.7 2.7 3 —

As shown in Comparative Example 6, when the hole-transporting layer wasformed of the compound A-10 as a single layer, although a higherefficiency could be obtained as compared with Comparative Example 4where the compound B-1 was used, the driving voltage became high toshorten the device life.

As shown in Table 3, the compound A-10 has an extremely small holemobility. Thus, its film thickness is increased with an increase indriving voltage. It can be assumed that, since the amount of holesinjected in the emitting layer was reduced due to an increased drivingvoltage, electrons arrived even at the hole-transporting layer todeteriorate hole-transporting materials, thereby shortening the devicelife. As compared with the compound B-1, the compound A-10 had aslightly smaller electron affinity, and a higher electron-blockingproperty, and hence, could enhance efficiency.

If the hole-injecting layer was inserted as in Comparative Examples 3and 4, the driving voltage was lowered as compared with the case wherethe hole-transporting layer formed of the compound A-10 was used as asingle layer. However, the driving voltage was still higher as comparedwith the device fabricated in Comparative Example 1 which had aconventional device configuration. It can be assumed that the drivingvoltage could not be lowered sufficiently due to insufficient holemobility of the compound E-2.

On the other hand, the devices fabricated in Examples 1 to 18 exhibiteda high luminous efficiency and a prolonged device life withoutincreasing the drive voltage. Use of the compound B-1 in thehole-injecting layer suppressed an increase in the driving voltage dueto a high hole mobility of the compound B-1.

The results of Comparative Example 1 demonstrate that use of thecompound E-1 increased driving voltage and shortened device life. Theresults show that the conventional stepwise setting of the ionizationpotential level of a hole-transporting material is not necessarilyeffective in realizing a low-voltage, highly-efficient, and long-liveddevice.

The organic EL device of the invention has a structure in which holesreadily flow due to the use of specific materials, thereby significantlyincreasing the amount of holes injected in the emitting layer. Inaddition, electrons are prevented from reaching the hole-transportinglayer, resulting in a prolonged device life. Moreover, a lower drivingvoltage and a more prolonged device life can be realized by maintainingthe characteristic property of enhancing an efficiency of the compoundA-10.

It can be assumed that the above-mentioned tendency can be observed whenanalogous compounds of each compound are used.

The similar tendency can be observed when an acceptor material is usedat the interface of the anode. Use of an acceptor material resulted in afurther lowered driving voltage.

INDUSTRIAL APPLICABILITY

The organic EL device of the invention can be used as an organic ELdevice which emits not only blue light but also various other colors,and is suitable for use in the fields of various displays, back light,light source, indicators, signboards, interiors and the like. It isparticularly suitable for a display device of color displays.

What is claimed is:
 1. An organic electroluminescent device comprising:an anode, a cathode, an emitting layer which is interposed between thecathode and the anode, and a hole-injecting/hole-transporting regionbetween the anode and the emitting layer; wherein the emitting layercomprises a material of formula (i)

wherein Ar is a substituted or unsubstituted condensed aromatic grouphaving 10 to 50 nucleus carbon atoms, Ar′ is a substituted orunsubstituted aromatic group having 6 to 50 nucleus carbon atoms, X¹ toX³ are independently a substituted or unsubstituted aromatic grouphaving 6 to 50 nucleus carbon atoms, a substituted or unsubstitutedaromatic heterocyclic group having 5 to 50 nucleus atoms, a substitutedor unsubstituted alkyl group having 1 to 50 carbon atoms, a substitutedor unsubstituted alkoxy group having 1 to 50 carbon atoms, a substitutedor unsubstituted aralkyl group having 7 to 50 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 50 nucleus atoms,a substituted or unsubstituted arylthio group having 6 to 50 nucleusatoms, a substituted or unsubstituted alkoxycarbonyl group having 2 to50 carbon atoms, a carboxyl group, a halogen atom, a cyano group, anitro group or a hydroxyl group; a, b and c are independently an integerof 0 to 4; and n is an integer of 1 to 3, provided that, when n is twoor more, the groups in may be the same or different; and a layer in thehole-injecting/hole-transporting region comprises a compound of formula(7)

wherein one of Ar₁₇ and Ar₁₈ is an optionally substituted biphenylgroup, and the other is an optionally substituted phenyl group or anoptionally substituted naphthyl group, and when substituted, thesubstituents on Ar₁₇ and Ar₁₈ are independently a phenyl group, naphthylgroup, or a linear or branched alkyl group having 1 to 6 carbon atoms,R₆ to R₁₃ are each independently a hydrogen atom, a phenyl group, anaphthyl group, or a linear or branched alkyl group having 1 to 6 carbonatoms, and L₄ is a biphenyl group selected from the group consisting of:

provided that an asterisk (*) indicates the position bonding to thenitrogen atom of the carbazolyl group, and R groups are eachindependently a hydrogen atom, a phenyl group, a naphthyl group, or alinear or branched alkyl group having 1 to 6 carbon atoms.
 2. Theorganic electroluminescent device according to claim 1, wherein in theformula (7), R₆ to R₁₃ and R groups are each independently a hydrogenatom or a linear or branched alkyl group having 1 to 6 carbon atoms. 3.The organic electroluminescent device according t claim 1, wherein inthe formula (7), R₆ to R₁₃ and R groups are a hydrogen atom.
 4. Theorganic electroluminescent device according to claim 1, wherein Ar is asubstituted or unsubstituted naphthyl group.
 5. The organicelectroluminescent device according to claim 1, wherein Ar′ is asubstituted or unsubstituted naphthyl group.
 6. The organicelectroluminescent device according to claim 1, wherein a, b and c arean integer of
 0. 7. The organic electroluminescent device according toclaim 1, wherein n is an integer of
 1. 8. An organic electroluminescentdevice comprising: an anode, a cathode, an emitting layer which isinterposed between the cathode and the anode, and ahole-injecting/hole-transporting region between the anode and theemitting layer; wherein the emitting layer comprises a material offormula (ii)

wherein Ar¹ and Ar² are independently a substituted or unsubstitutedaromatic ring group having 6 to 50 nucleus carbon atoms; and m and n areindependently an integer of 1 to 4, provided that in the case wherem=n=1 and Ar¹ and Ar² are symmetrically bonded to the benzene rings, Ar¹and Ar² are not the same, and in the case where m or n is an integer of2 to 4, m is different from n; and R¹ to R¹⁰ are independently ahydrogen atom, a substituted or unsubstituted aromatic ring group having6 to 50 nucleus carbon atoms, a substituted or unsubstituted aromaticheterocyclic group having 5 to 50 nucleus atoms, a substituted orunsubstituted alkyl group having 1 to 50 carbon atoms, a substituted orunsubstituted cycloalkyl group, a substituted or unsubstituted alkoxygroup having 1 to 50 carbon atoms, a substituted or unsubstitutedaralkyl group having 7 to 50 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 50 nucleus atoms, a substitutedor unsubstituted arylthio group having 6 to 50 nucleus atoms, asubstituted or unsubstituted alkoxycarbonyl group having 2 to 50 carbonatoms, a substituted or unsubstituted silyl group, a carboxyl group, ahalogen atom, a cyano group, a nitro group or a hydroxy group; and alayer in the hole-injecting/hole-transporting region comprises acompound of formula (7)

wherein one of Ar₁₇ and Ar₁₈ is an optionally substituted biphenylgroup, and the other is an optionally substituted phenyl group or anoptionally substituted naphthyl group, and when substituted, thesubstituents on Ar₁₇ and Ar₁₈ are independently a phenyl group, naphthylgroup, or a linear or branched alkyl group having 1 to 6 carbon atoms,R₆ to R₁₃ are each independently a hydrogen atom, a phenyl group, anaphthyl group, or a linear or branched alkyl group having 1 to 6 carbonatoms, and L₄ is a biphenyl group selected from the group consisting of:

provided that an asterisk(*) indicates the position bonding to thenitrogen atom of the carbazolyl group, and R groups are eachindependently a hydrogen atom, a phenyl group, a naphthyl group, or alinear or branched alkyl group having 1 to 6 carbon atoms.
 9. An organicelectroluminescent device comprising: an anode, a cathode, an emittinglayer which is interposed between the cathode and the anode, and ahole-injecting/hole-transporting region between the anode and theemitting layer; wherein the emitting layer comprises a material offormula (iv)

wherein A¹ and A² are independently a substituted or unsubstitutedcondensed aromatic ring group having 10 to 20 nucleus carbon atoms; Ar¹and Ar² are independently a hydrogen atom or a substituted orunsubstituted aromatic ring group with 6 to 50 nucleus carbon atoms; R¹to R¹⁰ are independently a hydrogen atom or a substituted orunsubstituted aromatic ring group having 6 to 50 nucleus carbon atoms, asubstituted or unsubstituted aromatic heterocyclic group having 5 to 50nucleus atoms, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, asubstituted or unsubstituted aralkyl group having 7 to 50 carbon atoms,a substituted or unsubstituted aryloxy group having 6 to 50 nucleusatoms, a substituted or unsubstituted arylthio group having 6 to 50nucleus atoms, a substituted or unsubstituted alkoxycarbonyl grouphaving 2 to 50 carbon atoms, a substituted or unsubstituted silyl group,a carboxyl group, a halogen atom, a cyano group, a nitro group or ahydroxy group, Each of Ar¹, Ar², R⁹ and R¹⁰ may be plural, and adjacentgroups thereof may form a saturated or unsaturated ring structure; andprovided that in the formula (iv), groups do not symmetrically bond to 9and 10 positions of the central anthracene with respect to X-Y axis; anda layer in the hole-injecting/hole-transporting region comprises acompound of

wherein one of Ar₁₇ and Ar₁₈ is an optionally substituted biphenylgroup, and the other is an optionally substituted phenyl group or anoptionally substituted naphthyl group, and when substituted, thesubstituents on Ar₁₇ and Aris are independently a phenyl group, naphthylgroup, or a linear or branched alkyl group having 1 to 6 carbon atoms,R₆ to R₁₃ are each independently a hydrogen atom, a phenyl group, anaphthyl group, or a linear or branched alkyl group having 1 to 6 carbonatoms, and L₄ is a biphenyl group selected from the group consisting of:

provided that an asterisk(*) indicates the position bonding to thenitrogen atom of the carbazolyl group, and R groups are eachindependently a hydrogen atom, a phenyl group, a naphthyl group, or alinear or branched alkyl group having 1 to 6 carbon atoms.